version-bump gulp-sass (the latest node-sass breaks compatibility with 2.0... I think)

package.json

@@ -24,7 +24,7 @@
     "gulp": "~3.8.11",
     "gulp-autoprefixer": "~3.0.2",
     "gulp-rename": "^1.2.2",
-    "gulp-sass": "~2.0.4",
+    "gulp-sass": "~2.3.1",
     "gulp-sourcemaps": "~1.5.2",
     "gulp-util": "~2.2.14",
     "isparta": "^4.0.0",