Add setuptools for python3.12

Author: samuelhwilliams

tox.ini

@@ -16,7 +16,9 @@ python =
 
 [testenv]
 description = run py.test tests
-deps = -r requirements-test.txt
+deps =
+  -r requirements-test.txt
+  setuptools
 commands =
   # this ugly hack is here because:
   # https://github.com/tox-dev/tox/issues/149