Install Python 3.11 for the format job to match nox session requirement

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: pavel-kirienko

.github/workflows/test.yml

@@ -47,6 +47,8 @@ jobs:
           submodules: recursive
       - uses: actions/setup-python@v6
         with:
-          python-version: "3.13"
+          python-version: |
+            3.11
+            3.13
       - run: pip install nox
       - run: nox -s format