Test with Python 3.13.0a6

Author: befeleme

.github/workflows/check.yml

@@ -22,7 +22,7 @@ jobs:
       fail-fast: false
       matrix:
         py:
-          - "3.13.0-alpha.2"
+          - "3.13.0-alpha.6"
           - "3.12"
           - "3.11"
           - "3.10"