Automated release process that supports multiple versions

[michael-small]

The learning curve for our more formal release process has hit some issues:

#229 (comment)

#230

We are exploring options to help automate this problem

Two suggestions, from @rainerhahnekamp

• The Backport Tool: https://github.com/sorenlouv/backport
• Changesets workflow: https://github.com/changesets/changesets

[michael-small]

My WIP backport GH action repo, for future reference: https://github.com/michael-small/backport-action-test

[michael-small]

Notes on the Backport Action

• Made my own repo. Made a v19 branch to backport to. Figured out various things then made a test PR to link to this toolkit issue.
• Test PR: link to toolkit issue michael-small/backport-action-test#14. Since this succeeded, notice that there is a link to the backported PR.
• Backported PR: [v19] Merge pull request #14 from michael-small/link-to-issue michael-small/backport-action-test#15. Simple as merging.
• Failed PR before this: Update README.md michael-small/backport-action-test#11. It says that if you want to manually backport to run backport --pr 11, but I don't know where to run it.
• If something is failing in the actions, the tag should be removed or it seems like it keeps trying on old PRs