chore(ci): 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 from https://github.com/openfga/sdk-generator/pull/297

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

[rhamzeh]

This seems very weird as I don't get what is tying the github action to PyPi, but this is what their documentation says, so let's merge!