Update NAT Gateway information in documentation

Added note about Standard V2 SKU NAT Gateway support.

Author: bowen5

articles/container-apps/custom-virtual-networks.md

@@ -129,6 +129,9 @@ You can use NAT Gateway to simplify outbound connectivity for your outbound inte
 
 When you configure a NAT Gateway on your subnet, the NAT Gateway provides a static public IP address for your environment. All outbound traffic from your container app is routed through the NAT Gateway's static public IP address.
 
+> [!NOTE]
+> Standard V2 SKU NAT Gateway is currently not supported for integration.
+
 ## Managed resources
 
 When you deploy an internal or an external environment into your own network, a new resource group is created in the Azure subscription where your environment is hosted. This resource group contains infrastructure components managed by the Azure Container Apps platform. Don't modify the services in this group or the resource group itself.