Deps: Bump the dependencies group

Bumps the dependencies group in /backport-pull-request with 2 updates: [black](https://github.com/psf/black) and [platformdirs](https://github.com/platformdirs/platformdirs).


Updates `black` from 24.4.0 to 24.4.2
- [Release notes](https://github.com/psf/black/releases)
- [Changelog](https://github.com/psf/black/blob/main/CHANGES.md)
- [Commits](psf/black@24.4.0...24.4.2)

Updates `platformdirs` from 4.2.0 to 4.2.1
- [Release notes](https://github.com/platformdirs/platformdirs/releases)
- [Changelog](https://github.com/platformdirs/platformdirs/blob/main/CHANGES.rst)
- [Commits](platformdirs/platformdirs@4.2.0...4.2.1)

---
updated-dependencies:
- dependency-name: black
  dependency-type: indirect
  update-type: version-update:semver-patch
  dependency-group: dependencies
- dependency-name: platformdirs
  dependency-type: indirect
  update-type: version-update:semver-patch
  dependency-group: dependencies
...

Signed-off-by: dependabot[bot] <support@github.com>