Create github workflow for releases

[masklinn]

The release workflow is not super impossible but it's a bit annoying:

• PR to bump version
• merge PR
• fetch result
• tag commit commit
• push tag
• twine

Doing that via a workflow could be easier, and less reliant on just remembering stuff (and thus forgetting it). It would also make the addition of more release tasks (e.g. github releases?) simpler.

It looks like GHA supports some number of inputs, which would be useful for e.g. the release manager's token, key (for twine's signing of the package), the release name, ...

Note: twine creates signature files so these could probably be used to create the release? And maybe sign the tag as well?

[masklinn]

Example from simonw's demo project: https://github.com/simonw/pids/blob/main/.github/workflows/publish.yml