CI - do not test using Python 3.9 anymore

Author: macbre

.github/workflows/python-ci.yml

@@ -18,7 +18,6 @@ jobs:
         # https://github.com/actions/python-versions/blob/main/versions-manifest.json
         # https://devguide.python.org/versions/#supported-versions
         python-version:
-        - "3.9"
         - "3.10"
         - "3.11"
         - "3.12"