Update GraphNode.cs

Author: Lempireqc

GraphDiff/GraphDiff/Internal/Graph/GraphNode.cs

@@ -16,6 +16,7 @@ internal class GraphNode
 
         public GraphNode Parent { get; private set; }
         public Stack<GraphNode> Members { get; private set; }
+        public bool? AllowDelete { get; set; }
 
         protected readonly PropertyInfo Accessor;