Test on latest python 3.13

Author: rhpvorderman

.github/workflows/ci.yml

@@ -62,6 +62,7 @@ jobs:
           - "3.10"
           - "3.11"
           - "3.12"
+          - "3.13-dev"
           - "pypy-3.9"
           - "pypy-3.10"
         os: ["ubuntu-latest"]