GitHub changes how authorship of sqush commits are attributed, breaks workflows

> It looks like the change we've made has a bug in it which means the PR author isn't getting a co-author credit on the squashed commit. We're working on a fix for that now, and I think that's the cause of a large part of the problem here (and explains why you're not seeing the co-author show up in GitHub

> PRs with a single author are an interesting case. We originally considered doing the above in the case where the commit message is not changed during merging. Doing so would introduce an inconsistency with other squash and merge commits, though, so we wanted to ship and learn here. It's also worth noting that the command line equivalent, git merge --squash, makes the merger the author of the commit.