Bump django from 2.2.16 to 2.2.28

Bumps [django](https://github.com/django/django) from 2.2.16 to 2.2.28.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@2.2.16...2.2.28)

---
updated-dependencies:
- dependency-name: django
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

setup.py

@@ -49,7 +49,7 @@
         'kombu==5.1.0',
         'ffs>=0.0.8.2',
         'Jinja2==2.10.1',
-        'django==2.2.16',
+        'django==2.2.28',
         'requests==2.25.0',
         'djangorestframework==3.12.2',
         'django-reversion==3.0.8',