Bump beautifulsoup4 to 4.11.x

Fixes #8797

setup.py

@@ -28,7 +28,7 @@ install_requires = [
     "django-filter>=2.2,<23",
     "draftjs_exporter>=2.1.5,<3.0",
     "Pillow>=4.0.0,<10.0.0",
-    "beautifulsoup4>=4.8,<4.10",
+    "beautifulsoup4>=4.8,<4.12",
     "html5lib>=0.999,<2",
     "Willow>=1.4,<1.5",
     "requests>=2.11.1,<3.0",