Automatically create GitHub release after successful Docker image publish

[mfisher87]

It's easy to forget to do this. We can auto-generate the release notes too.

[mfisher87]

This automation will look something like this one that I use on my personal site to make a release with every push to main.

We want this to be dependent instead on our existing workflow that starts with pushing a tag, then publishes a Docker image. This can be added as a final step IFF the workflow was triggered by a tag.