Pin Python 3.13 on Windows to a3

Author: radarhere

.github/workflows/test-windows.yml

@@ -32,7 +32,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["pypy3.10", "pypy3.9", "3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["pypy3.10", "pypy3.9", "3.8", "3.9", "3.10", "3.11", "3.12", "3.13.0-alpha.3"]
 
     timeout-minutes: 30