[Commit]: Add a README for making releases

[David Edelsohn]

Hi, Nick

Thanks for managing the release and for creating the README.  It's
great to have the release process documented.

One piece of feedback that I received on Twitter is the announcement
should include or link to some release notes.  At least an automated
list of the Bugzilla fixes that are included in the release.

Thanks for alerting me to the release so that I could announce it on
social media.

Thanks, David