Gitlab 13.3 changed so now pipelines started by developers run
inside the main repo, even for MRs. So we must explicitly add
the source repo to the git environment and use it.
Also, explictily say the formatting test doesn't need any other jobs
so that it will run in parallel with the main build, otherwise it
won't run until the test stage starts.
Don't interrupt the compilation pipelines, instead let
them finish. That will ensure the author of the change
gets notified if their push breaks something.
Mark Roszko
Ian McInerney
Seth Hillbrand