We fetch some packages to support the pip_parse rule
https://github.com/bazelbuild/rules_python/blob/996025317896846267c40ef1934b9e71e3445e8b/python/pip_install/repositories.bzl#L7-L78
which users have to install for us in their WORKSPACE, either with

load("@rules_python//python/pip_install:repositories.bzl", "pip_install_dependencies")
pip_install_dependencies()

or just by calling pip_parse from their WORKSPACE which also does this.

Now I'm adding support under #99 for publishing packages, and per the official documentation https://packaging.python.org/en/latest/tutorials/packaging-projects/#uploading-the-distribution-archives the twine utility is recommended for doing this.

Therefore we ought to fetch that tool. We'd have to decide whether we always do that under pip_install_dependencies along with the others, even though install and publish are really separate concerns. OR, users who want to publish would need to be told to add another incantation to WORKSPACE to fetch the twine tool. We also have to update the bzlmod example to match whatever we do.