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`.
import re
import json
import yaml
import logging
import traceback
import moto.cloudformation.utils
from six import iteritems
from six import string_types
from localstack.utils import common
from localstack.utils.aws import aws_stack
ACTION_CREATE = 'create'
PLACEHOLDER_RESOURCE_NAME = '__resource_name__'
LOG = logging.getLogger(__name__)
UPDATEABLE_RESOURCES = ['Lambda::Function', 'ApiGateway::Method']
def str_or_none(o):
    return o if o is None else json.dumps(o) if isinstance(o, (dict, list)) else str(o)
def select_attributes(obj, attrs):
    result = {}
    for attr in attrs:
        if obj.get(attr) is not None:
            result[attr] = str_or_none(obj.get(attr))
    return result
def get_bucket_location_config(**kwargs):
    return {'LocationConstraint': aws_stack.get_region()}
def lambda_get_params():
    return lambda params, **kwargs: params