FeedItem: Added deconstructor

src/TensorFlowNET.Core/Sessions/FeedItem.cs

@@ -16,5 +16,11 @@
 
         public static implicit operator FeedItem((object, object) feed)
             => new FeedItem(feed.Item1, feed.Item2);
+
+        public void Deconstruct(out object key, out object value)
+        {
+            key = Key;
+            value = Value;
+        }
     }
 }