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 re.match(r'/restapis/[^/]+/documentation/versions', path):
            if response.status_code == 404:
                return requests_response({'position': '1', 'items': []})
        
        if method == 'POST' and path == '/restapis':
            content = json.loads(to_str(response.content))
            event_publisher.fire_event(event_publisher.EVENT_APIGW_CREATE_API,
                payload={'a': event_publisher.get_hash(content['id'])})
        api_regex = r'^/restapis/([a-zA-Z0-9\-]+)$'
        if method == 'DELETE' and re.match(api_regex, path):
            api_id = re.sub(api_regex, r'\1', path)
            event_publisher.fire_event(event_publisher.EVENT_APIGW_DELETE_API,
                payload={'a': event_publisher.get_hash(api_id)})
def invoke_rest_api(api_id, stage, method, invocation_path, data, headers, path=None):
    path = path or invocation_path
    relative_path, query_string_params = extract_query_string_params(path=invocation_path)
    path_map = helpers.get_rest_api_paths(rest_api_id=api_id)
    try:
        extracted_path, resource = get_resource_for_path(path=relative_path, path_map=path_map)
    except Exception:
        return make_error('Unable to find path %s' % path, 404)
    integrations = resource.get('resourceMethods', {})
    integration = integrations.get(method, {})
    if not integration:
        integration = integrations.get('ANY', {})
    integration = integration.get('methodIntegration')