tests: fix CI image name

Author: hartungstenio

.github/workflows/tests.yml

@@ -20,7 +20,7 @@ jobs:
           - {name: Python 3.10, python: '3.10', os: ubuntu}
           - {name: Python 3.11, python: '3.11', os: ubuntu}
           - {name: Python 3.12, python: '3.12', os: ubuntu}
-          - {name: Python 3.12, python: '3.13', os: ubuntu}
+          - {name: Python 3.13, python: '3.13', os: ubuntu}
     steps:
       - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python }}