lib/plugins/aws/customResources/resources/cognitoUserPool/handler.js/update
function update(event, context) {
  const { Region, AccountId } = getEnvironment(context);
  const { FunctionName, UserPoolName, UserPoolConfigs } = event.ResourceProperties;

  const lambdaArn = getLambdaArn(Region, AccountId, FunctionName);

  return updateConfiguration({
    lambdaArn,
    userPoolName: UserPoolName,
    userPoolConfigs: UserPoolConfigs,
    region: Region,
  });
}