workflows: bump Python version

Signed-off-by: Benjamin Gilbert <bgilbert@cs.cmu.edu>

Author: bgilbert

.github/workflows/validate.yml

@@ -19,7 +19,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v6
         with:
-          python-version: '3.12'
+          python-version: '3.13'
       - name: Install dependencies
         run: python -m pip install pre-commit
       - name: Cache pre-commit environments