Create a re-usable GitHub Workflow to publish releases attached to a tag using this tool

The mystmd project created a little github workflow that can be re-used across projects here:

https://github.com/jupyter-book/mystmd/blob/main/.github/workflows/publish-github-release.yml

It is repository-agnostic! We should create a version of that workflow in this repository and ask others to re-use it if they wish.