DOC: Add Python version PyPI trove classifier metadata

Author: matthewfeickert

setup.py

@@ -22,6 +22,10 @@
     },
     classifiers=[
         "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
+        "Programming Language :: Python :: 3.11",
         "License :: OSI Approved :: MIT License",
         "Operating System :: OS Independent",
     ],