Use same python versions for TCK as for tests

Author: ishymko

.github/workflows/run-tck.yaml

@@ -29,7 +29,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.10", "3.11", "3.12"]
+        python-version: ['3.10', '3.13']
     steps:
       - name: Checkout a2a-python
         uses: actions/checkout@v4