Drop 3.9 from test matrix, add 3.13

Author: stefmolin

.github/workflows/env-checks.yml

@@ -42,7 +42,7 @@ jobs:
         fail-fast: false
         matrix:
             os: [macos-latest, ubuntu-latest, windows-latest]
-            python-version: ["3.9", "3.10", "3.11", "3.12"]
+            python-version: ["3.10", "3.11", "3.12", "3.13"]
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps: