bsnes/docs/release.md

Release checklist

1. Commit the new release
2. Tag the commit
3. git push --tags origin master to push the commit and tag at the same time.
4. Go to the docs admin and verify that it's building the new version as 'stable' and under its tag name.
5. Check out the libretro branch.
6. Merge changes from master.
7. git push to make the new changes available.