Version bump beautifulsoup to 4.8.x (#5817)

CONTRIBUTORS.rst

@@ -432,6 +432,7 @@ Contributors
 * Simon Evans
 * Arkadiusz Michał Ryś
 * James O'Toole
+* jeromelebleu
 
 Translators
 ===========

setup.py

@@ -28,7 +28,7 @@ install_requires = [
     "djangorestframework>=3.7.4,<4.0",
     "draftjs_exporter>=2.1.5,<3.0",
     "Pillow>=4.0.0,<7.0.0",
-    "beautifulsoup4>=4.5.1,<4.6.1",
+    "beautifulsoup4>=4.8,<4.9",
     "html5lib>=0.999,<2",
     "Unidecode>=0.04.14,<2.0",
     "Willow>=1.3,<1.4",