Update badge for 2023
.. .. image:: https://readthedocs.org/projects/skeleton/badge/?version=latest
.. :target: https://skeleton.readthedocs.io/en/latest/?badge=latest
-.. image:: https://img.shields.io/badge/skeleton-2022-informational
+.. image:: https://img.shields.io/badge/skeleton-2023-informational
:target: https://blog.jaraco.com/skeleton
