I can't find any announcements about it, but you can try it out: open a PR based on master, then push a separate commit (or merge a different PR) to master and

I can't find any announcements about it, but you can try it out: open a PR based on master, then push a separate commit (or merge a different PR) to master and return to your original PR. If you scroll down, there will be a box saying the base branch is out of date and a button asking to resync with master. If you click it, they will merge the master branch into your PR. I'm not sure if there are specific settings required for this to work. For example, we have the master branch protected and require the status checks to pass and the PR to be up to date before it can be merged.