Update UPDATE.md

Author: Chris Wiechmann

UPDATE.md

@@ -123,7 +123,7 @@ The solution ships the latest available Elastic version with new releases. Howev
 Watch this video to see a demonstration how to update the Elastic-Stack:  
 [![Update Elastic-Stack](https://img.youtube.com/vi/Oht_Xnzurok/0.jpg)](https://youtu.be/Oht_Xnzurok)
 
-#### 3 Elasticsearch nodes required
+### 3 Elasticsearch nodes required
 
 :exclamation: Before proceeding, make sure that your Elasticsearch cluster consists of __at least 3 nodes__. For example 3 Elasticsearch nodes running on two machines is perfectly fine for this.  
 There are 3 Elasticsearch nodes required, as there must always be a master node in the cluster. If this master node is stopped, a quorum of remaining cluster nodes must still be running to elect a new master, otherwise an upgraded Elasticsearch node cannot join the cluster. [Learn more](https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-discovery-quorums.html)