fixup! Test with Python 3.10, 3.11, and 3.12

Author: twm

.github/workflows/tests.yaml

@@ -42,7 +42,7 @@ jobs:
 
         include:
           # Run non-python version specific jobs.
-          - python-version: 3.12
+          - python-version: 3.9
             tox-env: mypy,apidocs
             skip-coverage: true