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`.
' lambci/lambda:%s'
                ) % (docker_cmd, container_name, env_vars_str, network_str, runtime)
                LOG.debug(cmd)
                run(cmd)
                LOG.debug('Copying files to container "%s" from "%s".' % (container_name, lambda_cwd))
                cmd = (
                    '%s cp'
                    ' "%s/." "%s:/var/task"'
                ) % (docker_cmd, lambda_cwd, container_name)
                LOG.debug(cmd)
                run(cmd)
                LOG.debug('Starting container: %s' % container_name)
                cmd = '%s start %s' % (docker_cmd, container_name)
                LOG.debug(cmd)
                run(cmd)
                
                time.sleep(1)
            
            LOG.debug('Getting the entrypoint for image: lambci/lambda:%s' % runtime)
            cmd = (
                '%s image inspect'
                ' --format="{{ .ContainerConfig.Entrypoint }}"'
                ' lambci/lambda:%s'
            ) % (docker_cmd, runtime)
            LOG.debug(cmd)
            run_result = run(cmd)
            entry_point = run_result.strip('[]\n\r ')
            container_network = self.get_docker_container_network(func_arn)
            LOG.debug('Using entrypoint "%s" for container "%s" on network "%s".'
                % (entry_point, container_name, container_network))