CI: use "ubuntu-latest" runner and current Python

Author: airtower-luna

.github/workflows/test.yaml

@@ -8,10 +8,10 @@ jobs:
     strategy:
       matrix:
         python:
-          - '3.9'
-          - '3.10'
+          - '3.12'
+          - '3.13'
     name: Python ${{ matrix.python }}
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python }}