Fix CONTRIBUTING.md
The CONTRIBUTING.md points to https://github.com/zeke/semantic-pull-requests. This shows
⚠️ THIS SERVICE IS NO LONGER MAINTAINED ⚠️
I have not looked into other conventional commmits checker, so I cannot recommend any alternatives. In our project(s) we don't use them (yet).
In my view, one should prefer the squash and merge feature of GitHub, where a repository maintiner can edit the final commit message to fit his taste. I do know that squash-merged could be hard in exceptional scenarios; but there is a jbang script to please git to handle it correctly.
My main reason is that Force pushing breaks Reviews, makes them disappear and prevents contributors to work in parallel.
Sure, of course we could squash-merge and edit the message, but that's only useful in those cases where there is a "dirty" commit history or if we're not interested in retaining the different commits that make up the PR. But often we do want that. In those cases it's important that each commit is properly marked. Heck, we forget sometimes. And we don't want unmarked commit merged into main just because we were sleepy :-)
Personally I don't mind force pushes, most PRs are one-person jobs. In that case I'd prefer clean commit histories that can be merged as-is. Of course once there are more people working on a single PR you should avoid force pushing.