Add release notes for rbintegrations 0.5 RC 1.

Review Request #9346 — Created Nov. 4, 2017 and submitted — Latest diff uploaded

Information

rbintegrations
master
db184a5...

Reviewers

This is a small release that just fixes an e-mail being sent out to the
CircleCI user. Along with the release notes, a stale comment about that
bug has been removed.

Built the docs and read through them. Checked for errors.