[ci] Update actions to python 3.12 (#7308)

.github/workflows/pregenerate.yml

@@ -18,10 +18,10 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
-      - name: Set up Python 3.9
+      - name: Set up Python 3.12
         uses: actions/setup-python@v5
         with:
-          python-version: 3.9
+          python-version: '3.12'
       - name: Install jinja
         run: python -m pip install jinja2
       - name: Install protobuf dependencies