Add tests with Python 3.13

Author: flashcode

.github/workflows/ci.yml

@@ -21,6 +21,7 @@ jobs:
           - "3.10"
           - "3.11"
           - "3.12"
+          - "3.13"
 
     name: Python ${{ matrix.python-version }} on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}