Guardrail no longer supports Custom Http Status Codes

from B. Tarricone -

A mapping for http status codes was added in a later version that causes custom http status codes to fail client generation. https://github.com/twilio/guardrail/blob/master/modules/codegen/src/main/scala/com/twilio/guardrail/generators/AkkaHttpGenerator.scala#L216-L289

akka-http supports custom statuses https://github.com/akka/akka-http/blob/master/akka-http-core/src/main/scala/akka/http/scaladsl/model/StatusCode.scala#L77

We need custom http status code support because we have a service that proxies requests to other providers and we overload the custom status code to indicate that the provider has returned an error back. The actual real status code are used to indicate issues with the actual proxy service