Update to labeler v5 conventions

[Zeitsperre]

Pull Request Checklist:

• [ ] This PR addresses an already opened issue (for bug fixes / features)
  • This PR fixes #xyz
• [ ] (If applicable) Documentation has been added / updated (for bug fixes / features).
• [ ] (If applicable) Tests have been added.
• [ ] This PR does not seem to break the templates.
• [ ] CHANGES.rst has been updated (with summary of main changes).
  • [ ] Link to issue (:issue:number) and pull request (:pull:number) has been added.

What kind of change does this PR introduce?

• Updates the label action configuration to the new API

Does this PR introduce a breaking change?

No, but more granular control is possible with the label action.

Other information:

https://github.com/actions/labeler