Bump djangorestframework-stubs from 3.14.5 to 3.15.0

Bumps [djangorestframework-stubs](https://github.com/typeddjango/djangorestframework-stubs) from 3.14.5 to 3.15.0.
- [Release notes](https://github.com/typeddjango/djangorestframework-stubs/releases)
- [Commits](typeddjango/djangorestframework-stubs@3.14.5...3.15.0)

---
updated-dependencies:
- dependency-name: djangorestframework-stubs
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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