Add release workflow

[carmocca]

The release steps are simple. They are done manually at the moment. They could be automated into a workflow dispatch action so that anybody can click the button.

Current steps:

• Have a clean clone of litgpt. This avoids accidentally uploading undesired artifacts.
• Make sure that the version in pyproject.toml is the one you want to upload.
• python3 -m build
• python3 -m twine upload --repository litgpt dist/*
• (Optional) Make a commit bumping the version (to a dev version normally)

Additionally, this workflow could also create and push a git tag.

More information on this topic: https://packaging.python.org/en/latest/tutorials/packaging-projects/

[rasbt]

Maybe we could optionally also make a tag for the release version. This could come in handy when debugging user issues.

Otherwise, this looks good, it's also what I usually did for my packages. We could add this as a maintainer-notes.md file or so for future reference in addition to making a workflow for this.

[carmocca]

Yes, I mentioned it above:

Additionally, this workflow could also create and push a git tag.

Another common alternative is that creating the tag itself triggers the release process. Either option is good