chore(python): Update the python version in docs presubmit to use 3.10 (#2045)

chore(python): Update the python version in docs to use 3.10

Author: parthea

synthtool/gcp/templates/python_library/.github/workflows/docs.yml

@@ -12,7 +12,7 @@ jobs:
     - name: Setup Python
       uses: actions/setup-python@v5
       with:
-        python-version: "3.9"
+        python-version: "3.10"
     - name: Install nox
       run: |
         python -m pip install --upgrade setuptools pip wheel