changing Type to IaasVM

Author: pikumarmsft16

src/ResourceManager/AzureBackup/Commands.AzureBackup/Cmdlets/Item/GetAzureBackupItem.cs

@@ -40,7 +40,7 @@ public class GetAzureBackupItem : AzureBackupContainerCmdletBase
         public string Status { get; set; }
 
         [Parameter(Mandatory = false, HelpMessage = AzureBackupCmdletHelpMessage.Type)]
-        [ValidateSet("VM")]
+        [ValidateSet("IaasVM")]
         public string Type { get; set; }
 
         public override void ExecuteCmdlet()