finish migrating release process to github actions

[mcfunley]

Currently there are some manual steps:

• Update the version in pyproject.toml
• Update the version in pugsql/__init__.py
• Push the code.
• Run bin/release

bin/release does the following:

• Runs some checks (to make sure that the versions updated above agree, and that the tests pass).
• Tags the release and pushes.
• Builds the documentation (using pdoc)
• Attempts to wait for pypi to have the new version, before updating the docs site so that it reflects the most recent version.
• Pushes the docs site.

This was put in place years ago before actions existed. A lot of that is redundant or convoluted. We can probably simplify a lot of this.