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`.
if resource_type not in UPDATEABLE_RESOURCES:
        LOG.warning('Unable to update resource type "%s", id "%s"' % (resource_type, resource_id))
        return
    LOG.info('Updating resource %s of type %s' % (resource_id, resource_type))
    props = resource['Properties']
    if resource_type == 'Lambda::Function':
        client = aws_stack.connect_to_service('lambda')
        keys = ('FunctionName', 'Role', 'Handler', 'Description', 'Timeout', 'MemorySize', 'Environment', 'Runtime')
        update_props = dict([(k, props[k]) for k in keys if k in props])
        if 'Code' in props:
            client.update_function_code(FunctionName=props['FunctionName'], **props['Code'])
        return client.update_function_configuration(**update_props)
    if resource_type == 'ApiGateway::Method':
        client = aws_stack.connect_to_service('apigateway')
        integration = props.get('Integration')
        
        kwargs = {
            'restApiId': props['RestApiId'],
            'resourceId': props['ResourceId'],
            'httpMethod': props['HttpMethod'],
            'requestParameters': props.get('RequestParameters')
        }
        if integration:
            kwargs['type'] = integration['Type']
            kwargs['integrationHttpMethod'] = integration.get('IntegrationHttpMethod')
            kwargs['uri'] = integration.get('Uri')
            return client.put_integration(**kwargs)
        kwargs['authorizationType'] = props.get('AuthorizationType')
        return client.put_method(**kwargs)
def convert_data_types(func_details, params):