ci: ensure we bump crate versions for "release worthy" changes

[thomaseizinger]

We have a policy to bump a crates version if we make a "release worthy" change to it. Normally, this is also accompanied with a changelog entry.

Anything that does not exclusively touch the lockfile is a release worthy change to me. This for example includes #4358.

We should have a CI check that ensures that the crate's version is bumped to $currentPatchOnCratesIo + 1. Such CI check would help us maintainers to remember this policy and also help users in making contributions because they can make self-directed changes based on the CI result.

[thomaseizinger]

Some more thoughts:

• I think we may want to make this check based on git tags and not crates.io otherwise CI is not deterministic and we will have weird failures when backporting things.
• A check for touching the changelog could also be interesting and I think quite easy. Essentially, all we'd need to do is verify, that the top-most line of the changelog is a version that does not exist as a git tag (if any files for that crate have been touched in that PR).

[thomaseizinger]

• (if any files for that crate have been touched in that PR).

Checking that should be quite easy with the gh CLI. See https://stackoverflow.com/a/68682405.