Fix crash when opening marketplace

plugins/Marketplace/PackageModel.py

@@ -31,7 +31,7 @@ class PackageModel(QObject):
         :param parent: The parent QML object that controls the lifetime of this model (normally a PackageList).
         """
         super().__init__(parent)
-        QQmlEngine.setObjectOwnership(self, QQmlEngine.CppOwnership)
+        QQmlEngine.setObjectOwnership(self, QQmlEngine.ObjectOwnership.CppOwnership)
         self._package_manager: CuraPackageManager = cast(CuraPackageManager, CuraApplication.getInstance().getPackageManager())
         self._plugin_registry: PluginRegistry = CuraApplication.getInstance().getPluginRegistry()