Add release notes for Review Board 3.0.1.

Review Request #9425 — Created Dec. 4, 2017 and submitted — Latest diff uploaded

Information

Review Board
release-3.0.x
100f68b...

Reviewers

This is a small release that adds a new permission for viewing
invite-only groups, fixes problems with avatars, and brings in other
fixes from the upcoming 2.5.17 release.

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