[ci] Set Python 3.13 in QA-checks step

Author: nemesifier

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v6
         with:
-          python-version: 3.x
+          python-version: "3.13"
 
       - name: Install Dependencies
         id: deps