chore(tox): Enable 3.12 and 3.13 tests in tox

Author: effigies

setup.cfg

@@ -81,7 +81,7 @@ envlist =
     black
     flake8
     mypy
-    {py37,py38,py39,py310,py311,pypy3}-toxlatest
+    {py37,py38,py39,py310,py311,py312,py313,pypy3}-toxlatest
 
 [gh-actions]
 python =
@@ -91,6 +91,7 @@ python =
     3.10: py310
     3.11: py311, black, flake8, mypy
     3.12: py312
+    3.13: py313
     pypy-3: pypy3
 
 [testenv]