Bump Python version

Author: hugovk

.github/workflows/update-calendar.yml

@@ -16,7 +16,7 @@ jobs:
         repository: fedora-python/python-release-schedule-ical
     - uses: actions/setup-python@v5
       with:
-        python-version: '3.8'
+        python-version: '3.13'
     - uses: dschep/install-pipenv-action@v1
     - name: Install dependencies
       run: pipenv install