Test with Python 3.13

Author: sciencewhiz

.github/workflows/workflow.yml

@@ -68,7 +68,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['pypy3.9', '3.8', '3.9', '3.10', '3.11', '3.12']
+        python-version: ['pypy3.9', '3.8', '3.9', '3.10', '3.11', '3.12', '3.13']
         sphinx-version: ['>=5,<6', '>=6a0,<7', '>=7,<7.3']
         os: [windows-latest, macos-latest, ubuntu-latest]
     steps: