Update proxy-buffers.md

Author: jaesoni

articles/application-gateway/proxy-buffers.md

@@ -85,5 +85,5 @@ For reference, visit [Azure SDK for .NET](/dotnet/api/microsoft.azure.management
 
 ## Limitations
 - API version 2020-01-01 or later should be used to configure buffers.
-- Currently, these changes are not supported through Portal.
+- Currently, these changes are not supported through Portal and PowerShell.
 - Request and Response Buffers can only be disabled for the WAF v2 SKU if request body checking is disabled. Otherwise, Request and Response Buffers cannot be disabled for the WAF v2 SKU.