From: Don Zickus on gitlab.com https://gitlab.com/cki-project/kernel-ark/-/issues/32#note_453843747
That is stale document data. Your clone should set you up at os-build (default branch) and everything should just work as expected. The 'master' branch just follows upstream but is merged nightly into os- build.
If you run the 'git clone' command or just run 'git fetch origin' and then git checkout os-build. You should be able to run 'make dist-srpm' and build the srpm to pass to koji.
Does that work?