Currently if a scratch build is run with a different downstream branch (like a private branch) the build fails because it defaults to running on the main branch.

Example build:
https://main-jenkins-csb-crwqe.apps.ocp-c1.prod.psi.redhat.com/job/DS_CI/job/get-sources-rhpkg-container-build_3.x/5027/console

Failing command:
brew container-build devspaces-3-rhel-8-containers-candidate git+https://pkgs.devel.redhat.com/git/containers/devspaces-udi#4048d31a2cb9ab76f58e1d632590ae12fd4634fb --git-branch devspaces-3-rhel-8 --nowait --scratch

Command that worked:
brew container-build devspaces-3-rhel-8-containers-candidate git+https://pkgs.devel.redhat.com/git/containers/devspaces-udi#4048d31a2cb9ab76f58e1d632590ae12fd4634fb, devspaces-3-rhel-8-containers-candidate,