We put milestone manually after we merge PR.
This should be automatic.
https://www.jessesquires.com/blog/2022/08/04/automatically-assign-milestones-with-github-actions/
https://github.com/orgs/community/discussions/26724#discussioncomment-3253107
Or something special for us. As sometimes pull request needs to marked with milestone as it is referred in commit, but it is rare case we can skip it if this is complicated.