Updated change log

Author: MiYanni

src/ResourceManager/Network/ChangeLog.md

@@ -19,6 +19,7 @@
 -->
 ## Current Release
 * Fix overwrite message 'Are you sure you want to overwriteresource'
+* Updated Set-AzureRmApplicationGatewayBackendAddressPool documentation to remove deprecated example
 
 ## Version 5.1.0
 * Added -AsJob support for long-running Network cmdlets. Allows selected cmdlets to run in the background and return a job to track and control progress.