Update Python matrix (#51)

* Update Python matrix

* Remove 3.13

Author: fabaff

.github/workflows/pythonpackage.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [ 3.9, "3.10", "3.11" ]
+        python-version: [ "3.10", "3.11", "3.12" ]
 
     steps:
     - uses: actions/checkout@v4