Merge branch 'bump-bleach' into 'master'

Bump Python requirement bleach to 5.0.0

See merge request !1658

requirements.txt

@@ -2,7 +2,7 @@
 
 apistar==0.7.2
 git+https://gitlab.com/teklia/apistar.git#egg=apistar
-bleach==4.1.0
+bleach==5.0.0
 django-admin-hstore-widget==1.1.0
 django-cors-headers==3.11.0
 django-enumfields==2.1.1