adding labeling per topic

[Borda]

What does this PR do?

automate topic assignment and improve triaging
drawback could be if a generic PR is touching almost all files

Before submitting

• Was this discussed/agreed via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure to update the docs?
• Did you write any new necessary tests?

PR review

Anyone in the community is free to review the PR once the tests have passed.
If we didn't discuss your PR in Github issues there's a high chance it will not be merged.

Did you have fun?

Make sure you had fun coding 🙃

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📚 Documentation preview 📚: https://torchmetrics--2024.org.readthedocs.build/en/2024/

[codecov]

Codecov Report

Merging #2024 (2e2fd9c) into master (1b184f4) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@          Coverage Diff           @@
##           master   #2024   +/-   ##
======================================
  Coverage      87%     87%           
======================================
  Files         275     275           
  Lines       15649   15649           
======================================
  Hits        13548   13548           
  Misses       2101    2101