Document release process in repo

[bpringe]

We should document the release process in docs/RELEASE.md.

Things to document:

• The happy path
• Troubleshooting

  • What to do when the publish script succeeds but the integration tests fail

    • Revert the changelog change that the publish script created and committed
    • Remove the version tag both in the local and remote repo that the publish script added

  • What to do when the "Merge published into dev" step of the calva-io-build workflow fails with the below output

    ! [rejected]            HEAD -> dev (non-fast-forward)
    error: failed to push some refs to 'git@github.com:BetterThanTomorrow/calva.git'
    hint: Updates were rejected because the tip of your current branch is behind
    hint: its remote counterpart. Integrate the remote changes (e.g.
    hint: 'git pull ...') before pushing again.
    hint: See the 'Note about fast-forwards' in 'git push --help' for details.
    
    Exited with code exit status 1
    

    • git checkout dev && git pull && git merge origin/published --no-ff -m "Merge branch published into dev [skip ci]"