Version bump django-redis to 4.11.0 for Django 3.0 support

requirements/production.txt

@@ -13,5 +13,5 @@ django-storages==1.7.2
 # For retrieving credentials and signing requests to Elasticsearch
 botocore==1.12.33
 aws-requests-auth==0.4.0
-django-redis==4.8.0
+django-redis==4.11.0
 django_cache_url==2.0.0