python3Packages.pytest-forked: don't propagate pytest

pytest extensions should not propagate pytest. Doing so makes it
impossible to combine the package with another version of pytest, which
sometimes is needed.

pkgs/development/python-modules/pytest-forked/default.nix

@@ -18,7 +18,13 @@ buildPythonPackage rec {
 
   nativeBuildInputs = [ setuptools_scm ];
 
-  propagatedBuildInputs = [ py pytest ];
+  buildInputs = [
+    pytest
+  ];
+
+  propagatedBuildInputs = [
+    py
+  ];
 
   checkInputs = [ pytestCheckHook ];