[msailes]

Issue #, if available:
N/A

Description of changes:
Added support for the IAMPolicy response as part of a API Gateway custom authorizer.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[msailes]

From https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-lambda-authorizer.html

{
  "principalId": "abcdef", 
  "policyDocument": {
    "Version": "2012-10-17",
    "Statement": [
      {
        "Action": "execute-api:Invoke",
        "Effect": "Allow|Deny",
        "Resource": "arn:aws:execute-api:{regionId}:{accountId}:{apiId}/{stage}/{httpVerb}/[{resource}/[{child-resources}]]"
      }
    ]
  },
  "context": {
    "exampleKey": "exampleValue"
  }
}

[msailes]

Slight misunderstanding here.

Because this is a response object, there isn't a serialization change needed to Lambda.

However with the current dependencies I'm not sure how to response with capitalized Version and Statement.