YARN-8568. Replace the deprecated zk-address property in the HA config example in ResourceManagerHA.md (bsteinbach via rkanter)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/ResourceManagerHA.md

@@ -111,7 +111,7 @@ Here is the sample of minimal setup for RM failover.
   <value>master2:8088</value>
 </property>
 <property>
-  <name>yarn.resourcemanager.zk-address</name>
+  <name>hadoop.zk.address</name>
   <value>zk1:2181,zk2:2181,zk3:2181</value>
 </property>
 ```