Add latest free threaded python to tox and ci.

Author: Edward Girling

.github/workflows/tests.yaml

@@ -14,6 +14,7 @@ jobs:
       matrix:
         include:
           - {python: '3.14'}
+          - {name: free-threaded-latest, python: '3.14t'}
           - {python: '3.13'}
           - {name: Windows, python: '3.13', os: windows-latest}
           - {name: Mac, python: '3.13', os: macos-latest}

pyproject.toml

@@ -143,6 +143,7 @@ order-by-type = false
 [tool.tox]
 env_list = [
     "py3.14", "py3.13", "py3.12", "py3.11", "py3.10",
+    "py3.14t",
     "pypy3.11",
     "style",
     "typing",