- Remove multi-version project. I wish I could make this work, but I
don't think it's feasible right now.
- Add 1.19.x (well, 1.19.4) and 1.20.x.
- Use publish instead of uploadAll for publishing.
I really wanted to use includeBuild instead of include here, but it
doesn't work very well with genIntellijRuns right now - I think we might
need to do some more magic to fix that.