upgrade code test matrix

Author: Conengmo

.github/workflows/test_code.yml

@@ -12,10 +12,10 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest]
-        python-version: ["3.8", "3.12"]
+        python-version: ["3.9", "3.13"]
         experimental: [false]
         include:
-          - python-version: "3.12"
+          - python-version: "3.13"
             os: "ubuntu-latest"
             experimental: true
       fail-fast: false