Since commits will be squashed and merged in GitHub, we only
require one of the commits to contain a Change-ID within a
pull request
Change-Id: I0fbb1c0e79009097456193fbe3c6fa20746e4805
This updates the change-id code to refer to commit messages in
pull requests instead of on pushes.
Change-Id: I308f02b4616804b386140d5875a79878eccd721e