Add trusted publishing to PyPI and Test PyPI

[illia-v]

TODO:

• Create GitHub environments named pypi-publish and test-pypi-publish in the repo settings.
• Configure trusted publishers on PyPI and Test PyPI.

[illia-v]

Unlike for urllib3, I'd like to avoid the added complexity of something like hatch-vcs for generating dev versions published to Test PyPI. We can just rely on github.run_number instead. Note that the dev number won't be reset when the actual version is changed.

[illia-v]

@sethmlarson please create GitHub environments named pypi-publish and test-pypi-publish https://github.com/sethmlarson/socksio/settings/environments