updating DIRECTORY.md

Author: github-actions

DIRECTORY.md

@@ -20,6 +20,7 @@
   * Graph
     * [Graph](https://github.com/TheAlgorithms/Javascript/blob/master/Data-Structures/Graph/Graph.js)
   * Heap
+    * [MaxHeap](https://github.com/TheAlgorithms/Javascript/blob/master/Data-Structures/Heap/MaxHeap.js)
     * [MinPriorityQueue](https://github.com/TheAlgorithms/Javascript/blob/master/Data-Structures/Heap/MinPriorityQueue.js)
   * Linked-List
     * [DoublyLinkedList](https://github.com/TheAlgorithms/Javascript/blob/master/Data-Structures/Linked-List/DoublyLinkedList.js)