Update release notes
Update release notes

- Add version bump commit message template

- Verify the checksum

- Add mail headers template suitable for use with mutt(1)

DBOTW/pick,DBOTW/pick,calleerlandsson/pick,calleerlandsson/pick,thoughtbot/pick,calleerlandsson/pick,DBOTW/pick,thoughtbot/pick,thoughtbot/pick,thoughtbot/pick