Create a bot to check if there is a CHANGES entry for new PRs

[stefanvodita]

Description

We always have to remind ourselves and others to add a CHANGES entry. We can probably write a GitHub action to check for changes to that file on every new PR and leave a comment warning the author if that's missing.

[prudhvigodithi]

Here is the sample PR with change-log verifier action added prudhvigodithi#1, we can add the same workflow to lucene repo. But I see the error dangoslen/changelog-enforcer@v3 is not allowed to be used in apache/lucene.

[javanna]

Yes to this! It would be great to combine this with setting the milestone :)

[stefanvodita]

@prudhvigodithi - I opened #13898 inspired by your PR, tested it on my fork, and it's working correctly.
@javanna - I like that idea! Maybe we can do that as a follow-up.