Lima mesa is not a fork of upstream mesa

Gitlab won't let you make merge requests to repos that aren't related somehow, which means that I can't use my personal mesa repo (forked from mesa/mesa) to make merge requests. What's worse is that trying to fork this repo gives me a "name already taken" error, even after I tried renaming my existing repo, which means that it's impossible for anyone in my situation to submit a MR without being able to push to this repo. I don't think there's a way to mark a repo as a fork of another after the fact in gitlab, so this repo needs to be deleted and recreated :(