python3Packages.apischema: pin to pytest 8.3.x

pkgs/development/python-modules/apischema/default.nix

···
   fetchFromGitHub,
   graphql-core,
   pytest-asyncio,
-  pytestCheckHook,
+  pytest8_3CheckHook,
   pythonOlder,
   setuptools,
 }:
···
 
   nativeCheckInputs = [
     pytest-asyncio
-    pytestCheckHook
+    pytest8_3CheckHook
   ]
   ++ lib.flatten (builtins.attrValues optional-dependencies);