python3Packages.qscintilla: add setuptools

pkgs/development/python-modules/qscintilla-qt5/default.nix

···
 
   disabled = !isPy3k;
 
-  nativeBuildInputs = [ sip qmake pyqt-builder qscintilla ];
+  nativeBuildInputs = [ sip qmake pyqt-builder qscintilla pythonPackages.setuptools ];
   buildInputs = [ qtbase ];
   propagatedBuildInputs = [ pyqt5 ] ++ lib.optionals stdenv.isDarwin [ qtmacextras ];