Test Python 3.13

Author: jdavid

.github/workflows/tests.yml

@@ -15,7 +15,7 @@ jobs:
         - os: ubuntu-22.04
           python-version: 3.9
         - os: ubuntu-22.04
-          python-version: '3.12'
+          python-version: '3.13-dev'
         - os: ubuntu-22.04
           python-version: 'pypy3.9'
         - os: macos-latest