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`.
stack_name = resources_map.get('AWS::StackName')
        resource_hash_key = (stack_name, logical_id)
        
        updating = CURRENTLY_UPDATING_RESOURCES.get(resource_hash_key)
        LOG.debug('Currently updating stack resource %s/%s: %s' % (stack_name, logical_id, updating))
        if updating:
            return None
        
        resource_tuple = parsing.parse_resource(logical_id, resource_json, resources_map)
        if not resource_tuple:
            return None
        _, resource_json, _ = resource_tuple
        
        props = resource_json['Properties'] = resource_json.get('Properties') or {}
        if resource_json['Type'] == 'AWS::Lambda::EventSourceMapping' and not props.get('StartingPosition'):
            props['StartingPosition'] = 'LATEST'
        
        resource = resources_map._parsed_resources.get(logical_id)
        if resource and not update:
            return resource
        
        resource_wrapped = {logical_id: resource_json}
        should_be_created = template_deployer.should_be_deployed(logical_id, resource_wrapped, stack_name)
        if not should_be_created:
            
            if not template_deployer.is_updateable(logical_id, resource_wrapped, stack_name):
                LOG.debug('Resource %s need not be deployed: %s' % (logical_id, resource_json))