add Python 3.13

.github/workflows/test.yml

@@ -6,7 +6,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12.3', pypy-3.8, pypy-3.9]
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12.3', '3.13.0-beta.4', pypy-3.8, pypy-3.9]
         exclude:
           - os: windows-latest
             python-version: pypy-3.8