Update TOC.yml

Added LB change migration guideline

Author: abhishjain002

articles/hdinsight/TOC.yml

@@ -172,7 +172,9 @@ items:
       - name: Ambari user configs migration
         href: ./migrate-ambari-recent-version-hdinsight.md
       - name: Upgrade to Apache Ranger in Azure HDInsight
-        href: ./hdinsight-ranger-5-1-migration.md   
+        href: ./hdinsight-ranger-5-1-migration.md
+      - name: Load balancer migration guidelines for Azure HDInsight
+        href: ./load-balancer-migration-guidelines.md
       - name: Hadoop
         items:
         - name: Motivation and benefits