Add free-threaded Python's test

Author: curegit

.github/workflows/test.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python_version: ['3.12', '3.13', '3.14']
+        python_version: ['3.12', '3.13', '3.14', '3.14t']
     steps:
       - name: Checkout
         uses: actions/checkout@v6