Requirements: django-cors-headers update to latest version

We are using Django 3.x now, so this problem should be solved now.

Author: humitos

requirements/pip.txt

@@ -92,10 +92,7 @@ dj-pagination==2.5.0
 # Version comparison stuff
 packaging==21.2
 
-# django-cors-middleware was replaced by django-cors-headers
-# django-cors-headers==3.10.0 is failing with:
-# AttributeError: 'dict' object has no attribute 'has_header'
-django-cors-headers==2.0.0  # pyup: ignore
+django-cors-headers==3.11.0
 
 # User agent parsing - used for analytics purposes
 user-agents==2.2.0