The following example `serverless.yml` fails to deploy on localstack:

```yaml
service: "localtest"

provider:
  name: "aws"
  runtime: "nodejs10.x"

functions:
  hello:
    handler: "handler.hello"
    
resources:
  Resources:
    ApiGatewayRestApi:
      Type: "AWS::ApiGateway::RestApi"
      Properties:
        Name: "${self:provider.stage}-${self:service}"
    GatewayResponseDefault400:
      Type: "AWS::ApiGateway::GatewayResponse"
      Properties:
        RestApiId:
          Ref: "ApiGatewayRestApi"
        ResponseType: "DEFAULT_4XX"
        ResponseTemplates:
          application/json: '{"errors":[{"message":"Custom text."}]}'
    GatewayResponseUnauthorized:
      Type: "AWS::ApiGateway::GatewayResponse"
      Properties:
        RestApiId:
          Ref: "ApiGatewayRestApi"
        ResponseType: "UNAUTHORIZED"
        ResponseTemplates:
          application/json: '{"errors":[{"message":"Custom text!", "extra":"Some extra info"}]}'
    GatewayResponseDefault500:
      Type: "AWS::ApiGateway::GatewayResponse"
      Properties:
        RestApiId:
          Ref: "ApiGatewayRestApi"
        ResponseType: "DEFAULT_5XX"
        ResponseTemplates:
          application/json: '{"errors":[{"message":$context.error.messageString}]}'
    GatewayResponseIntegrationTimeout:
      Type: "AWS::ApiGateway::GatewayResponse"
      Properties:
        RestApiId:
          Ref: "ApiGatewayRestApi"
        ResponseType: "INTEGRATION_TIMEOUT"
        ResponseTemplates:
          application/json: '{"errors":[{"message":$context.error.messageString}]}'

plugins:
- "serverless-localstack"

custom:
  localstack:
    stages:
      - "local"
```

The error on the localstack end is `Exception: CloudFormation deployment for resource type ApiGateway::GatewayResponse not yet implemented`.
return resolve_ref(stack_name, resource_id, resources,
                                attribute='PhysicalResourceId')
                        except Exception as e:
                            LOG.debug('Unable to extract physical id for resource %s: %s' % (resource_id, e))
                else:
                    if callable(prop_key):
                        prop_value = prop_key(resource_props, stack_name=stack_name, resources=resources)
                    else:
                        prop_value = resource_props.get(prop_key)
                    if prop_value is not None:
                        params[param_key] = prop_value
    
    for param_key, prop_keys in dict(params).items():
        tmp_value = params.get(param_key)
        if tmp_value is not None:
            params[param_key] = resolve_refs_recursively(stack_name, tmp_value, resources)
        
        if str(tmp_value).lower() in ['true', 'false']:
            params[param_key] = str(tmp_value).lower() == 'true'
    
    params = json.loads(aws_stack.fix_account_id_in_arns(json.dumps(params)))
    
    params = common.merge_recursive(defaults, params)
    
    params = convert_data_types(func_details, params)
    
    try:
        LOG.debug('Request for creating resource type "%s" in region %s: %s %s' % (
            resource_type, aws_stack.get_region(), func_details['function'], params))
        result = function(**params)