Bump django from 2.2.13 to 2.2.28

Bumps [django](https://github.com/django/django) from 2.2.13 to 2.2.28.
- [Release notes](https://github.com/django/django/releases)
- [Commits](django/django@2.2.13...2.2.28)

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

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

requirements.txt

@@ -2,7 +2,7 @@ certifi==2022.12.7
 chardet==3.0.4
 coreapi==2.3.3
 coreschema==0.0.4
-Django==2.2.13
+Django==2.2.28
 django-auth-ldap==1.7.0
 django-rest-swagger==2.2.0
 djangorestframework==3.11.2