After discussing with @mohanboddu, the following changes are needed for containers to use stream branches.

1. fedpkg container-build change to give it the right platform (f29, f30) to build against (might be possible to use the Dockerfile here to add the information)
2. Bodhi ? ( I don't think we need any changes in Bodhi but it is worth checking with @bowlofeggs )
3. fedpkg request-branch and request-repo to handle container requests
4. dist-git config changes if they have disabled stream branches on container namespace