Modify Python version exclusions in CI workflow

Author: benkiel

.github/workflows/run-tests.yml

@@ -22,13 +22,17 @@ jobs:
         platform: [ubuntu-latest, macos-latest, windows-latest]
         exclude: # Only test on the oldest and latest supported stable Python on macOS and Windows.
           - platform: macos-latest
-            python-version: 3.9
+            python-version: 3.11
           - platform: windows-latest
-            python-version: 3.9
+            python-version: 3.11
           - platform: macos-latest
-            python-version: 3.14
+            python-version: 3.12
           - platform: windows-latest
-            python-version: 3.14
+            python-version: 3.12
+          - platform: macos-latest
+            python-version: 3.13
+          - platform: windows-latest
+            python-version: 3.13
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}