Bump django-stubs-ext in /{{cookiecutter.project_name}} (#2697)

Bumps [django-stubs-ext](https://github.com/typeddjango/django-stubs) from 5.1.0 to 5.1.1.
- [Release notes](https://github.com/typeddjango/django-stubs/releases)
- [Commits](typeddjango/django-stubs@5.1.0...5.1.1)

---
updated-dependencies:
- dependency-name: django-stubs-ext
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>