Currently `signature.ValidRequest`[ in case of any error returns](https://github.com/messagebird/go-rest-api/blob/cb04299d9c5304255c5e77628578de3141a993e7/signature/signature.go#L117-L121) `Unknown host: {{request host}}` error. Such errors are not helpful in figuring out what went wrong. Especially because the host has nothing to do with signature verification.