docs(apim): List Configuration API as custom domain option

Author: tomkerkhove

articles/api-management/configure-custom-domain.md

@@ -45,6 +45,7 @@ There are several API Management endpoints to which you can assign a custom doma
 | **Developer portal (legacy)** | Default is: `<apim-service-name>.portal.azure-api.net` |
 | **Developer portal** | Default is: `<apim-service-name>.developer.azure-api.net` |
 | **Management** | Default is: `<apim-service-name>.management.azure-api.net` |
+| **Configuration API (v2)** | Default is: `<apim-service-name>.configuration.azure-api.net` |
 | **SCM** | Default is: `<apim-service-name>.scm.azure-api.net` |
 
 ### Considerations