Add Python 3.11 to classifiers

Since it's supported and is being tested by the CI workflow.

Signed-off-by: Kevin Locke <[email protected]>

Author: kevinoid

setup.cfg

@@ -36,6 +36,7 @@ classifiers =
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
+    Programming Language :: Python :: 3.11
     Programming Language :: Python :: Implementation :: CPython
     Programming Language :: Python :: Implementation :: PyPy
     Topic :: Software Development