Support installing arbitrary branches
It would be nice to use juliaup instead of building from source to test out feature branches of julia. I don't know what that syntax would look like, but maybe something similar to how Julia packages can be added to an environment by branch with the # symbol?
juliaup add #some-branch
See also: #852 #903 #842 #96 #14 #6
I think we should try to get the support for PRs in first. I'm not sure whether we can ever support arbitrary branches, because those are presumably not being built by the Julia CI infrastructure.
I think we should support all builds that have been built by the Julia CI infrastructure and not yet evicted from cache