demote python version again

Author: Tim Blume

.github/workflows/main.yaml

@@ -18,7 +18,7 @@ jobs:
     - uses: actions/checkout@v3
     - uses: actions/setup-python@v3
       with:
-        python-version: 3.13
+        python-version: 3.11
     - uses: crazy-max/ghaction-upx@v3
       with:
         install-only: true