python3Packages.pytest-xdist: 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-xdist/default.nix

@@ -22,8 +22,11 @@ buildPythonPackage rec {
   };
 
   nativeBuildInputs = [ setuptools_scm ];
+  buildInputs = [
+    pytest
+  ];
   checkInputs = [ pytestCheckHook filelock ];
-  propagatedBuildInputs = [ execnet pytest pytest-forked psutil ];
+  propagatedBuildInputs = [ execnet pytest-forked psutil ];
 
   # access file system
   disabledTests = [