[deps] Pinned django-filter to 21.1

(cherry picked from commit a53ebb9)

Author: pandafy

setup.py

@@ -56,7 +56,7 @@
         ],
         'rest': [
             'djangorestframework~=3.13.0',
-            'django-filter>=2.2.0<2.4.0',
+            'django-filter~=21.1',  # django-filter uses CalVer
             'drf-yasg~=1.20.0',
         ],
         'celery': ['celery~=5.2.3'],