Add CD workflow

[ravwojdyla]

Re: #154

This is based on sgkit's wheels workflow and https://packaging.python.org/en/latest/guides/publishing-package-distribution-releases-using-github-actions-ci-cd-workflows, the differences are:

• the workflow is designed for Trusted Publishing: https://packaging.python.org/en/latest/guides/publishing-package-distribution-releases-using-github-actions-ci-cd-workflows/#configuring-trusted-publishing
• I have moved the packaging + package testing from CI to CD workflow, but we could consider having it in both?
• the testpypi pushing happens on tag, but maybe it should happen on test branch? I'm not entirely sure what is the purpose of the test branch in this repo, but that's something to consider.

For this to work, @jeromekelleher you will need to configure Trusted Publishing as documented in the link above, copy pasting here:

1. Go to https://pypi.org/manage/account/publishing/.
   Fill in the name you wish to publish your new PyPI project under (the name value in your setup.cfg or pyproject.toml), the GitHub repository owner’s name (org or user), and repository name, and the name of the release workflow file under the .github/ folder, see Creating a workflow definition. Finally, add the name of the GitHub Environment (pypi) we’re going set up under your repository. Register the trusted publisher.

2. Now, go to https://test.pypi.org/manage/account/publishing/ and repeat the second step, but this time, enter testpypi as the name of the GitHub Environment.

3. Your “pending” publishers are now ready for their first use and will create your projects automatically once you use them for the first time.

[jeromekelleher]

I'm not entirely sure what is the purpose of the test branch in this repo, but that's something to consider.

This was just cruft - I've deleted it. We only have main now.

[jeromekelleher]

@benjeffery, you're better up on these ideas than me. Would you mind taking a look and commenting please?

[benjeffery]

This looks good to me - although I would keep the package tests in CI, or trigger this workflow on PRs, as otherwise failures will get missed.

[ravwojdyla]

@benjeffery sounds good, ptal 🙏

[jeromekelleher]

OK, I'm going to merge this and see how we go. Thanks @ravwojdyla!

[ravwojdyla]

@jeromekelleher thanks, https://github.com/sgkit-dev/bio2zarr/actions/runs/8938992174 has done just the packaging. According to the current implementation you would need to push a tag to get testpypi release https://github.com/sgkit-dev/bio2zarr/actions/runs/8938992174/workflow#L67. For the actual pypi test or prod push to work, @jeromekelleher as the owner of the project in pypi, you will need to configure the Trusted Publishing (instructions in the comments above).

[jeromekelleher]

Cool - I'll push a release in a few days and see how it goes. I think I've set up the trusted publisher stuff 🤞