Use Python 3.12 for nightly builds

.github/workflows/nightly.yml

@@ -43,7 +43,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.10"
+          python-version: "3.12"
       - name: Install dependencies
         run: |
             python -m pip install -U pip