chore: support Python 3.13

Author: janbritz

.github/workflows/ci.yml

@@ -13,5 +13,5 @@ jobs:
     uses: questionpy-org/.github/.github/workflows/python-ci.yml@v8.1
     with:
       # GitHub workflow inputs do not support lists, so we pass JSON.
-      pytest-python-versions: '["3.11", "3.12"]'
+      pytest-python-versions: '["3.11", "3.12", "3.13"]'
       packages: questionpy_common questionpy_server tests

.python-version

@@ -1,2 +1,3 @@
 3.11
 3.12
+3.13