Upgrade gulp-sass to 4.0.1 and rebuild package-lock.json with npm 6

The only difference to the generated code appears to be in sourcemap data.

client/package-lock.json

@@ -14,19 +14,19 @@
       "resolved": "https://registry.npmjs.org/yargs/-/yargs-4.7.1.tgz",
       "integrity": "sha1-5gQyZYozh/8mnAKOrN5KUS5Djf8=",
       "requires": {
-        "camelcase": "3.0.0",
-        "cliui": "3.2.0",
-        "decamelize": "1.2.0",
-        "lodash.assign": "4.0.9",
-        "os-locale": "1.4.0",
-        "pkg-conf": "1.1.3",
-        "read-pkg-up": "1.0.1",
-        "require-main-filename": "1.0.1",
-        "set-blocking": "1.0.0",
-        "string-width": "1.0.1",
-        "window-size": "0.2.0",
-        "y18n": "3.2.1",
-        "yargs-parser": "2.4.0"
+        "camelcase": "^3.0.0",
+        "cliui": "^3.2.0",
+        "decamelize": "^1.1.1",
+        "lodash.assign": "^4.0.3",
+        "os-locale": "^1.4.0",
+        "pkg-conf": "^1.1.2",
+        "read-pkg-up": "^1.0.1",
+        "require-main-filename": "^1.0.1",
+        "set-blocking": "^1.0.0",
+        "string-width": "^1.0.1",
+        "window-size": "^0.2.0",
+        "y18n": "^3.2.1",
+        "yargs-parser": "^2.4.0"
       },
       "dependencies": {
         "camelcase": {
@@ -39,9 +39,9 @@
           "resolved": "https://registry.npmjs.org/cliui/-/cliui-3.2.0.tgz",
           "integrity": "sha1-EgYBU3qRbSmUD5NNo7SNWFo5IT0=",
           "requires": {
-            "string-width": "1.0.1",
-            "strip-ansi": "3.0.1",
-            "wrap-ansi": "2.0.0"
+            "string-width": "^1.0.1",
+            "strip-ansi": "^3.0.1",
+            "wrap-ansi": "^2.0.0"
           },
           "dependencies": {
             "strip-ansi": {
@@ -49,7 +49,7 @@
               "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
               "integrity": "sha1-ajhfuIU9lS1f8F0Oiq+UJ43GPc8=",
               "requires": {
-                "ansi-regex": "2.0.0"
+                "ansi-regex": "^2.0.0"
               },
               "dependencies": {
                 "ansi-regex": {
@@ -64,7 +64,7 @@
               "resolved": "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-2.0.0.tgz",
               "integrity": "sha1-fTD4+HP5pbvDpk2ryNF34HGuQm8=",
               "requires": {
-                "string-width": "1.0.1"
+                "string-width": "^1.0.1"
               }
             }
           }
@@ -79,8 +79,8 @@
           "resolved": "https://registry.npmjs.org/lodash.assign/-/lodash.assign-4.0.9.tgz",
           "integrity": "sha1-Cgcx2TWQ3dm6RYn61lqvbuCSF+M=",
           "requires": {
-            "lodash.keys": "4.0.7",
-            "lodash.rest": "4.0.3"
+            "lodash.keys": "^4.0.0",
+            "lodash.rest": "^4.0.0"
           },
           "dependencies": {
             "lodash.keys": {
@@ -100,7 +100,7 @@
           "resolved": "https://registry.npmjs.org/os-locale/-/os-locale-1.4.0.tgz",
           "integrity": "sha1-IPnxeuKe00XoveWDsT0gCYA8FNk=",
           "requires": {
-            "lcid": "1.0.0"
+            "lcid": "^1.0.0"
           },
           "dependencies": {
             "lcid": {
@@ -108,7 +108,7 @@
               "resolved": "https://registry.npmjs.org/lcid/-/lcid-1.0.0.tgz",
               "integrity": "sha1-MIrMr6C8SDo4Z7S28rlQYlHRuDU=",
               "requires": {
-                "invert-kv": "1.0.0"
+                "invert-kv": "^1.0.0"
               },
               "dependencies": {
                 "invert-kv": {
@@ -125,10 +125,10 @@
           "resolved": "https://registry.npmjs.org/pkg-conf/-/pkg-conf-1.1.3.tgz",
           "integrity": "sha1-N45W1v0T6Iv7b0ol33qD+qvduls=",
           "requires": {
-            "find-up": "1.1.2",
-            "load-json-file": "1.1.0",
-            "object-assign": "4.1.0",
-            "symbol": "0.2.3"
+            "find-up": "^1.0.0",
+            "load-json-file": "^1.1.0",
+            "object-assign": "^4.0.1",
+            "symbol": "^0.2.1"
           },
           "dependencies": {
             "find-up": {
@@ -136,8 +136,8 @@
               "resolved": "https://registry.npmjs.org/find-up/-/find-up-1.1.2.tgz",
               "integrity": "sha1-ay6YIrGizgpgq2TWEOzK1TyyTQ8=",
               "requires": {
-                "path-exists": "2.1.0",
-                "pinkie-promise": "2.0.1"
+                "path-exists": "^2.0.0",
+                "pinkie-promise": "^2.0.0"
               },
               "dependencies": {
                 "path-exists": {
@@ -145,7 +145,7 @@
                   "resolved": "https://registry.npmjs.org/path-exists/-/path-exists-2.1.0.tgz",
                   "integrity": "sha1-D+tsZPD8UY2adU3V77YscCJ2H0s=",
                   "requires": {
-                    "pinkie-promise": "2.0.1"
+                    "pinkie-promise": "^2.0.0"
                   }
                 },
                 "pinkie-promise": {
@@ -153,7 +153,7 @@
                   "resolved": "https://registry.npmjs.org/pinkie-promise/-/pinkie-promise-2.0.1.tgz",
                   "integrity": "sha1-ITXW36ejWMBprJsXh3YogihFD/o=",
                   "requires": {
-                    "pinkie": "2.0.4"
+                    "pinkie": "^2.0.0"
                   },
                   "dependencies": {
                     "pinkie": {
@@ -170,11 +170,11 @@
               "resolved": "https://registry.npmjs.org/load-json-file/-/load-json-file-1.1.0.tgz",
               "integrity": "sha1-lWkFcI1YtLq0wiYbBPWfMcmTdMA=",
               "requires": {
-                "graceful-fs": "4.1.4",
-                "parse-json": "2.2.0",
-                "pify": "2.3.0",
-                "pinkie-promise": "2.0.1",
-                "strip-bom": "2.0.0"
+                "graceful-fs": "^4.1.2",
+                "parse-json": "^2.2.0",
+                "pify": "^2.0.0",
+                "pinkie-promise": "^2.0.0",
+                "strip-bom": "^2.0.0"
               },
               "dependencies": {
                 "graceful-fs": {
@@ -187,7 +187,7 @@
                   "resolved": "https://registry.npmjs.org/parse-json/-/parse-json-2.2.0.tgz",
                   "integrity": "sha1-9ID0BDTvgHQfhGkJn43qGPVaTck=",
                   "requires": {
-                    "error-ex": "1.3.0"
+                    "error-ex": "^1.2.0"
                   },
                   "dependencies": {
                     "error-ex": {
@@ -195,7 +195,7 @@
                       "resolved": "https://registry.npmjs.org/error-ex/-/error-ex-1.3.0.tgz",
                       "integrity": "sha1-5ntD8+gsluo6WE/+4Ln8MyXYAtk=",
                       "requires": {
-                        "is-arrayish": "0.2.1"
+                        "is-arrayish": "^0.2.1"
                       },
                       "dependencies": {
                         "is-arrayish": {
@@ -217,7 +217,7 @@
                   "resolved": "https://registry.npmjs.org/pinkie-promise/-/pinkie-promise-2.0.1.tgz",
                   "integrity": "sha1-ITXW36ejWMBprJsXh3YogihFD/o=",
                   "requires": {
-                    "pinkie": "2.0.4"
+                    "pinkie": "^2.0.0"
                   },
                   "dependencies": {
                     "pinkie": {
@@ -232,7 +232,7 @@
                   "resolved": "https://registry.npmjs.org/strip-bom/-/strip-bom-2.0.0.tgz",
                   "integrity": "sha1-YhmoVhZSBJHzV4i9vxRHqZx+aw4=",
                   "requires": {
-                    "is-utf8": "0.2.1"
+                    "is-utf8": "^0.2.0"
                   },
                   "dependencies": {
                     "is-utf8": {
@@ -261,8 +261,8 @@
           "resolved": "https://registry.npmjs.org/read-pkg-up/-/read-pkg-up-1.0.1.tgz",
           "integrity": "sha1-nWPBMnbAZZGNV/ACpX9AobZD+wI=",
           "requires": {
-            "find-up": "1.1.2",
-            "read-pkg": "1.1.0"
+            "find-up": "^1.0.0",
+            "read-pkg": "^1.0.0"
           },
           "dependencies": {
             "find-up": {
@@ -270,8 +270,8 @@
               "resolved": "https://registry.npmjs.org/find-up/-/find-up-1.1.2.tgz",
               "integrity": "sha1-ay6YIrGizgpgq2TWEOzK1TyyTQ8=",
               "requires": {
-                "path-exists": "2.1.0",
-                "pinkie-promise": "2.0.1"
+                "path-exists": "^2.0.0",
+                "pinkie-promise": "^2.0.0"
               },
               "dependencies": {
                 "path-exists": {
@@ -279,7 +279,7 @@
                   "resolved": "https://registry.npmjs.org/path-exists/-/path-exists-2.1.0.tgz",
                   "integrity": "sha1-D+tsZPD8UY2adU3V77YscCJ2H0s=",
                   "requires": {
-                    "pinkie-promise": "2.0.1"
+                    "pinkie-promise": "^2.0.0"
                   }
                 },
                 "pinkie-promise": {
@@ -287,7 +287,7 @@
                   "resolved": "https://registry.npmjs.org/pinkie-promise/-/pinkie-promise-2.0.1.tgz",
                   "integrity": "sha1-ITXW36ejWMBprJsXh3YogihFD/o=",
                   "requires": {
-                    "pinkie": "2.0.4"
+                    "pinkie": "^2.0.0"
                   },
                   "dependencies": {
                     "pinkie": {
@@ -304,9 +304,9 @@
               "resolved": "https://registry.npmjs.org/read-pkg/-/read-pkg-1.1.0.tgz",
               "integrity": "sha1-9f+qXs0pyzHAR0vKfXVra7KePyg=",
               "requires": {
-                "load-json-file": "1.1.0",
-                "normalize-package-data": "2.3.5",
-                "path-type": "1.1.0"
+                "load-json-file": "^1.0.0",
+                "normalize-package-data": "^2.3.2",
+                "path-type": "^1.0.0"
               },
               "dependencies": {
                 "load-json-file": {
@@ -314,11 +314,11 @@
                   "resolved": "https://registry.npmjs.org/load-json-file/-/load-json-file-1.1.0.tgz",
                   "integrity": "sha1-lWkFcI1YtLq0wiYbBPWfMcmTdMA=",
                   "requires": {
-                    "graceful-fs": "4.1.4",
-                    "parse-json": "2.2.0",
-                    "pify": "2.3.0",
-                    "pinkie-promise": "2.0.1",
-                    "strip-bom": "2.0.0"
+                    "graceful-fs": "^4.1.2",
+                    "parse-json": "^2.2.0",
+                    "pify": "^2.0.0",
+                    "pinkie-promise": "^2.0.0",
+                    "strip-bom": "^2.0.0"
                   },
                   "dependencies": {
                     "graceful-fs": {
@@ -331,7 +331,7 @@
                       "resolved": "https://registry.npmjs.org/parse-json/-/parse-json-2.2.0.tgz",
                       "integrity": "sha1-9ID0BDTvgHQfhGkJn43qGPVaTck=",
                       "requires": {
-                        "error-ex": "1.3.0"
+                        "error-ex": "^1.2.0"
                       },
                       "dependencies": {
                         "error-ex": {
@@ -339,7 +339,7 @@
                           "resolved": "https://registry.npmjs.org/error-ex/-/error-ex-1.3.0.tgz",
                           "integrity": "sha1-5ntD8+gsluo6WE/+4Ln8MyXYAtk=",
                           "requires": {
-                            "is-arrayish": "0.2.1"
+                            "is-arrayish": "^0.2.1"
                           },
                           "dependencies": {
                             "is-arrayish": {
@@ -361,7 +361,7 @@
                       "resolved": "https://registry.npmjs.org/pinkie-promise/-/pinkie-promise-2.0.1.tgz",
                       "integrity": "sha1-ITXW36ejWMBprJsXh3YogihFD/o=",
                       "requires": {
-                        "pinkie": "2.0.4"
+                        "pinkie": "^2.0.0"
                       },
                       "dependencies": {
                         "pinkie": {
@@ -376,7 +376,7 @@
                       "resolved": "https://registry.npmjs.org/strip-bom/-/strip-bom-2.0.0.tgz",
                       "integrity": "sha1-YhmoVhZSBJHzV4i9vxRHqZx+aw4=",
                       "requires": {
-                        "is-utf8": "0.2.1"
+                        "is-utf8": "^0.2.0"
                       },
                       "dependencies": {
                         "is-utf8": {
@@ -393,10 +393,10 @@
                   "resolved": "https://registry.npmjs.org/normalize-package-data/-/normalize-package-data-2.3.5.tgz",
                   "integrity": "sha1-jZJPFClg4Xd+f/4XBUNjHMfLAt8=",
                   "requires": {
-                    "hosted-git-info": "2.1.5",
-                    "is-builtin-module": "1.0.0",
-                    "semver": "5.1.0",
-                    "validate-npm-package-license": "3.0.1"
+                    "hosted-git-info": "^2.1.4",
+                    "is-builtin-module": "^1.0.0",
+                    "semver": "2 || 3 || 4 || 5",
+                    "validate-npm-package-license": "^3.0.1"
                   },
                   "dependencies": {
                     "hosted-git-info": {
@@ -409,7 +409,7 @@
                       "resolved": "https://registry.npmjs.org/is-builtin-module/-/is-builtin-module-1.0.0.tgz",
                       "integrity": "sha1-VAVy0096wxGfj3bDDLwbHgN6/74=",
                       "requires": {
-                        "builtin-modules": "1.1.1"
+                        "builtin-modules": "^1.0.0"
                       },
                       "dependencies": {
                         "builtin-modules": {
@@ -429,8 +429,8 @@
                       "resolved": "https://registry.npmjs.org/validate-npm-package-license/-/validate-npm-package-license-3.0.1.tgz",
                       "integrity": "sha1-KAS6vnEq0zeUWaz74kdGqywwP7w=",
                       "requires": {
-                        "spdx-correct": "1.0.2",
-                        "spdx-expression-parse": "1.0.2"
+                        "spdx-correct": "~1.0.0",
+                        "spdx-expression-parse": "~1.0.0"
                       },
                       "dependencies": {
                         "spdx-correct": {
@@ -438,7 +438,7 @@
                           "resolved": "https://registry.npmjs.org/spdx-correct/-/spdx-correct-1.0.2.tgz",
                           "integrity": "sha1-SzBz2TP/UfORLwOsVRlJikFQ20A=",
                           "requires": {
-                            "spdx-license-ids": "1.2.1"
+                            "spdx-license-ids": "^1.0.2"
                           },
                           "dependencies": {
                             "spdx-license-ids": {
@@ -453,8 +453,8 @@
                           "resolved": "https://registry.npmjs.org/spdx-expression-parse/-/spdx-expression-parse-1.0.2.tgz",
                           "integrity": "sha1-1SsUtelnB3FECvIlvLVjEirEUvY=",
                           "requires": {
-                            "spdx-exceptions": "1.0.4",
-                            "spdx-license-ids": "1.2.1"
+                            "spdx-exceptions": "^1.0.4",
+                            "spdx-license-ids": "^1.0.0"
                           },
                           "dependencies": {
                             "spdx-exceptions": {
@@ -478,9 +478,9 @@
                   "resolved": "https://registry.npmjs.org/path-type/-/path-type-1.1.0.tgz",
                   "integrity": "sha1-WcRPfuSR2nBNpBXaWkBwuk+P5EE=",
                   "requires": {
-                    "graceful-fs": "4.1.4",
-                    "pify": "2.3.0",
-                    "pinkie-promise": "2.0.1"
+                    "graceful-fs": "^4.1.2",
+                    "pify": "^2.0.0",
+                    "pinkie-promise": "^2.0.0"
                   },
                   "dependencies": {
                     "graceful-fs": {
@@ -498,7 +498,7 @@
                       "resolved": "https://registry.npmjs.org/pinkie-promise/-/pinkie-promise-2.0.1.tgz",
                       "integrity": "sha1-ITXW36ejWMBprJsXh3YogihFD/o=",
                       "requires": {
-                        "pinkie": "2.0.4"
+                        "pinkie": "^2.0.0"
                       },
                       "dependencies": {
                         "pinkie": {
@@ -529,9 +529,9 @@
           "resolved": "https://registry.npmjs.org/string-width/-/string-width-1.0.1.tgz",
           "integrity": "sha1-ySEptvHX9SrPmvQkom44ZKBc6wo=",
           "requires": {
-            "code-point-at": "1.0.0",
-            "is-fullwidth-code-point": "1.0.0",
-            "strip-ansi": "3.0.1"
+            "code-point-at": "^1.0.0",
+            "is-fullwidth-code-point": "^1.0.0",
+            "strip-ansi": "^3.0.0"
           },
           "dependencies": {
             "code-point-at": {
@@ -539,7 +539,7 @@
               "resolved": "https://registry.npmjs.org/code-point-at/-/code-point-at-1.0.0.tgz",
               "integrity": "sha1-9psZLT99keOC5Lcb3bd4eGGasMY=",
               "requires": {
-                "number-is-nan": "1.0.0"
+                "number-is-nan": "^1.0.0"
               },
               "dependencies": {
                 "number-is-nan": {
@@ -554,7 +554,7 @@
               "resolved": "https://registry.npmjs.org/is-fullwidth-code-point/-/is-fullwidth-code-point-1.0.0.tgz",
               "integrity": "sha1-754xOG8DGn8NZDr4L95QxFfvAMs=",
               "requires": {
-                "number-is-nan": "1.0.0"
+                "number-is-nan": "^1.0.0"
               },
               "dependencies": {
                 "number-is-nan": {
@@ -569,7 +569,7 @@
               "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
               "integrity": "sha1-ajhfuIU9lS1f8F0Oiq+UJ43GPc8=",
               "requires": {
-                "ansi-regex": "2.0.0"
+                "ansi-regex": "^2.0.0"
               },
               "dependencies": {
                 "ansi-regex": {
@@ -596,8 +596,8 @@
           "resolved": "https://registry.npmjs.org/yargs-parser/-/yargs-parser-2.4.0.tgz",
           "integrity": "sha1-HzZ9ycbPpWYLaXEjDzsnf8Xjrco=",
           "requires": {
-            "camelcase": "2.1.1",
-            "lodash.assign": "4.0.9"
+            "camelcase": "^2.1.1",
+            "lodash.assign": "^4.0.6"
           },
           "dependencies": {
             "camelcase": {

package.json

@@ -71,7 +71,7 @@
     "gulp-autoprefixer": "~4.0.0",
     "gulp-cssnano": "^2.1.2",
     "gulp-rename": "^1.2.2",
-    "gulp-sass": "^3.1.0",
+    "gulp-sass": "^4.0.1",
     "gulp-size": "^2.1.0",
     "gulp-sourcemaps": "~2.6.1",
     "gulp-util": "~3.0.8",