Workflow cleanup

[sarnold]

• move pypi upload to end of release.yml
• use gitchangelog action

Check the current github release flags and modify as needed, or leave a review comment and I'll push the changes:

          draft: false
          prerelease: false
          # uncomment below to upload wheels to github releases
          files: dist/cibw-wheels/pyre2*.whl

[andreasvc]

Thanks!