Remove old Python version from CI

Author: egeakman

.github/workflows/tests.yaml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         os: [macos-latest, windows-latest, ubuntu-latest]
-        python-version: ["3.9", "3.10", "3.11", "3.12.0-beta.4"]
+        python-version: ["3.10", "3.11", "3.12.0-beta.4"]
 
     steps:
       - name: Checkout code