Hook up to merge bot
We should hook up homu to this repo. The issue with "Squash and merge" is that you lose the semantics of separate commits and have a non-sensical commit msg that joins all the msgs. Commit msgs from fixup! commits also get in, which is yucky.
Let's install a basic testsuite that homu can gate on (I'm ignoring the existing PR tests we have now since as I mentioned before, it's conceptually not really appropriate for gating PRs). And from there, hook up homu.
Homu all the things!
Not opposed to this, but would like input on ideas on how to gate on PRs. We were working toward something a little more intelligent in our PAPR tests, but still have work to do in that space.