python: explicitly require 3.x (we're not that picky)

Author: ab9rf

.github/workflows/build-windows.yml

@@ -69,7 +69,9 @@ jobs:
     runs-on: windows-2022
     steps:
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
+        with:
+          python-version: '3.x'
       - name: Install build dependencies
         run: |
           choco install sccache