Does not support Github SCM material introduced by gocd-build-github-pull-requests

[hubx]

https://github.com/ashwanthkumar/gocd-build-github-pull-requests is used by many in combination with gocd to build and verify PRs

If you add any Github SCM material - the gomatic configuration will fail with:

  File ".../venv3/lib/python3.8/site-packages/gomatic/gocd/materials.py", line 28, in Materials
    raise RuntimeError("don't know of material matching " + ET.tostring(element, 'utf-8'))

For python3 you need to fix that to raise RuntimeError("don't know of material matching " + str(ET.tostring(element, 'utf-8'))) and you get a RuntimeError: don't know of material matching b'<scm ref="<uuid>" />\n '

I don't how the Github SCM works and if GitMaterial could be reused (the UI selectors in gocd look very similar)