Update metadata and dependencies for the packages for Review Bot 3.
Review Request #12160 — Created March 16, 2022 and submitted
This adds Python 3.10 as a supported version in the classifiers, adds
python_requiresmetadata to help
pipinstall the right wheels, and
updates our optional dependencies to install the correct versions for
the given version of Python.
Built the packages. Tested installation on Python 2.7 and all 3.x releases.