[OMPI devel] Github Actions: cherry-pick commit message checker

[Jeff Squyres (jsquyres) via devel]

I talked about this PR on the webex today:

    https://github.com/open-mpi/ompi/pull/8431

Comments / feedback would be welcome.

Unless I hear objections, I plan to merge this on master COB tomorrow (10 Feb 
2021).

Thanks!

-- 
Jeff Squyres
jsquy...@cisco.com