Remove github test running with python 3.9

Author: waldbaer

.github/workflows/python-pdm.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
+        python-version: ['3.10', '3.11', '3.12', '3.13', '3.14']
         os: [ubuntu-latest, macOS-latest, windows-latest]
 
     steps: