Bump django from 4.2.16 to 5.1.4

Bumps [django](https://github.com/django/django) from 4.2.16 to 5.1.4.
- [Commits](django/django@4.2.16...5.1.4)

---
updated-dependencies:
- dependency-name: django
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements/base.txt

@@ -1,5 +1,5 @@
 # Django
-django==4.2.17
+django==5.1.4
 django-allauth==0.63.6
 django-anymail[mailgun]==8.6
 django-autoslug==1.9.9  # https://github.com/justinmayer/django-autoslug