chore(python-sdk): enable PyPI trusted publishing

[evansims]

Description

This PR updates the Python SDK's GitHub publishing workflow to enable trusted publishing with the Python Package Index.

References

• Generated change for SDK repository: https://github.com/openfga/python-sdk/pull/64

Review Checklist

• [ ] I have clicked on "allow edits by maintainers".
• [ ] I have added documentation for new/changed functionality in this PR or in a PR to openfga.dev [Provide a link to any relevant PRs in the references section above]
• [x] The correct base branch is being used, if not main
• [ ] I have added tests to validate that the change in functionality is working as expected