Raise Python to 3.13 for VC2022 pipelines

Python 3.10.11 was removed from the runner's tool cache. Images
20261012.333 and earlier had it; 20261022.344 has only 3.13, 3.14 and
the new 3.15.0

While meson still supports Python 3.10+, raising it to 3.13 here seems
reasonable since 3.10 will still be tested in other pipelines.

.github/workflows/windows.yml

@@ -61,7 +61,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@v6
         with:
-          python-version: '3.10'
+          python-version: '3.13'
 
       - name: Setup MSVC
         uses: ilammy/msvc-dev-cmd@v1