Add free-threaded python3.14t to the testing

https://py-free-threading.github.io

Author: cclauss

.github/workflows/python_tests.yml

@@ -15,7 +15,7 @@ jobs:
       max-parallel: 5
       matrix:
         os: [macos-15-intel, macos-latest, ubuntu-latest] # , windows-latest]
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14", "3.14t"]
         include:
           - os: macos-26
             python-version: 3.x