message: Detect npm client in SummaryReporter
diff: @@ -132,10 +132,14 @@ class SummareReporter extends BaseReporter {
  let updateCommand;
  const event = process.env.npm_lifecycle_event;
  const prefix = NPM_EVENTS.has(event) ? '' : 'run ';
  + const client = typeof process.env.npm_config_user_agent === 'string' &&
  + process.env.npm_config_user_agent.match('yarn') !== null
  + ? 'yarn'
  + : 'npm';
  if (config.watch) {
  updateCommand = 'press `u`';
  } else if (event) {
  - updateCommand = `run with \`npm ${prefix + event} -- -u\``;
  + updateCommand = `run with \`${client + ' ' + prefix + event} -- -u\``;
  } else {
  updateCommand = 're-run with `-u`';
  }
  