Bump django from 2.0.2 to 2.2.28

Bumps [django](https://github.com/django/django) from 2.0.2 to 2.2.28.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@2.0.2...2.2.28)

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

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

requirements.txt

@@ -1,7 +1,7 @@
 celery==4.3.0
 certifi==2018.4.16
 chardet==3.0.4
-Django==2.0.2
+Django==2.2.28
 djangorestframework==3.7.7
 django-cors-headers==2.4.0
 django-filter==1.1.0