Configure automatically generated release notes

[jiribenes]

This issue is of very low importance, but we could generate more stratified release notes if we wanted to according to the PR labels.
By configuring some YAML file somewhere in the repository, we could say that, for example, everything with the area:llvm label is then in a special "LLVM" section. This could then help to produce easy-to-skim release notes.

See docs for more details: https://docs.github.com/en/repositories/releasing-projects-on-github/automatically-generated-release-notes#configuring-automatically-generated-release-notes

Testing this is a bit cumbersome, probably easier by making a fork of the repo and letting the autorelease.yml action run every day / running it manually.

Follow-up from #538.

[b-studios]

Yes, this is very low prio, even though it sounds cute.