Test Python 3.14 in CI

Author: srittau

.github/workflows/ci.yml

@@ -50,6 +50,7 @@ jobs:
           - "3.12.0"
           - "3.13"
           - "3.13.0"
+          - "3.14-dev"
           - "pypy3.8"
           - "pypy3.9"
           - "pypy3.10"