Update Profile change log

Author: cormacpayne

src/ResourceManager/Profile/ChangeLog.md

@@ -18,6 +18,8 @@
         - Additional information about change #1
 -->
 ## Current Release
+- Updated USGovernmentActiveDirectoryEndpoint to https://login.microsoftonline.us/
+    - For more information about the Azure Government endpoint mappings, please see the following: https://docs.microsoft.com/en-us/azure/azure-government/documentation-government-developer-guide#endpoint-mapping
 
 ## Version 4.0.0
 - Set-AzureRmDefault
@@ -106,4 +108,4 @@
 ## Version 2.3.0
 * Add-AzureRmAccount
     - Add position for Credential parameter so the following command is allowed: Add-AzureRmAccount (Get-Credential)
-    - Updated parameter sets so the SubscriptionId and SubscriptionName are mutually exclusive
+    - Updated parameter sets so the SubscriptionId and SubscriptionName are mutually exclusive