removing python version 3.9 from integration test matrix

Author: FrankJonasmoelle

.github/workflows/integration-tests.yaml

@@ -25,7 +25,7 @@ jobs:
           - "mnist-keras numpyhelper"
           - "mnist-pytorch numpyhelper"
           - "server-functions numpyhelper"
-        python_version: ["3.9", "3.10", "3.11", "3.12"]
+        python_version: ["3.10", "3.11", "3.12"]
         os:
           - ubuntu-24.04
     runs-on: ${{ matrix.os }}