Update badge for 2023

Author: jaraco

README.rst

@@ -14,5 +14,5 @@
 .. .. 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