Bump django from 4.2.11 to 4.2.15 in /requirements

Bumps [django](https://github.com/django/django) from 4.2.11 to 4.2.15.
- [Commits](django/django@4.2.11...4.2.15)

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

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

requirements/requirements-dev.txt

@@ -8,7 +8,7 @@ asgiref==3.6.0
     # via django
 dj-database-url==1.3.0
     # via -r requirements-dev.in
-django==4.2.11
+django==4.2.15
     # via
     #   -r requirements-dev.in
     #   dj-database-url