build(deps): update django-stubs requirement from ==5.0.* to ==5.1.*

Updates the requirements on [django-stubs](https://github.com/typeddjango/django-stubs) to permit the latest version.
- [Release notes](https://github.com/typeddjango/django-stubs/releases)
- [Commits](typeddjango/django-stubs@5.0.0...5.1.0)

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

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

requirements-test.txt

@@ -1,4 +1,4 @@
 coverage == 7.6.*
 pre-commit == 3.8.*
 tox == 4.21.*
-django-stubs == 5.0.*
+django-stubs == 5.1.*