Given an unsigned request, this function returns a SignedRequest record to be passed to Http.task https://package.elm-lang.org/packages/elm/http/latest/Http#task

AWS.signRequest config now rawRequest
    |> Result.map Http.task


-- Result String (Task x a)

Adds necessary X-Amz-Target http request header

See https://docs.aws.amazon.com/apigateway/api-reference/making-http-requests/

Options for AWS.awsTargetHeader