Add step to log the list of Boxo/Kubo commits in master/main that aren't making it into a release

[BigLep]

Done Criteria

The releaser sees the list of Boxo and Kubo commits that are in master/main that aren't being included in the current release.
The release issue is also updated with this information.

Why Important

Especially now that fixes are often made in Boxo but need to be bubbled up to Kubo, it's easier to have a Kubo release not include all the desired functionality. We had this in happen in 0.20 (see here). This either frustrates users and/or creates extra work for the maintainers having to do extra followup releases.

Notes

I hypothesize that seeing this list and having it get added to the release issue (which others are subscribed to) will help trigger if we're missing something important.

[BigLep]

@galargh : if possible, I'd like to improve this before 0.21. Also, if you have better ideas on how to do this rather than printing to console and posting to the release issue, feel free to share.

[BigLep]

@galargh : this is awesome - thank you!

I want to make sure that someone not executing the release will still have visibility into this set of commits that aren't included. If I understand correctly, the set of commits will make it into the release PR description. The release PR also references the release issue (which causes a backlink from the release issue to the release PR). As a result, it should be self-service for someone to discover and see this easily enough. Correct me if I have this wrong.

Thank you!

[galargh]

Yes! That's exactly right. The release PR is linked to the release issue so it should be quite easy for anyone to get to this information.