Extend CI matrix to Python 3.14

Author: schnellerhase

.github/workflows/pythonapp.yml

@@ -47,7 +47,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-22.04]
-        python-version: ["3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
     steps:
       - uses: actions/checkout@v5
       - name: Set up Python