message: feat(aio): add v6 release notification
  PR Close
diff: <mat-toolbar-row class="notification-container">
  <aio-notification
  icon="insert_comment"
  - iconLabel="Survey"
  - buttonText="Go to survey"
  - actionUrl="https://bit.ly/angular-survey-2018"
  - notificationId="survey-january-2018"
  - expirationDate="2018-01-19"
  + iconLabel="Announcement"
  + buttonText="Learn More"
  + actionUrl="https://blog.angular.io/version-6-0-0-of-angular-now-available-cc56b0efa7a4"
  + notificationId="angular-v6-announcement"
  + expirationDate="2018-07-01"
  (dismissed)="notificationDismissed()">
  - Help Angular by taking a <b>1 minute survey</b>!
  + Version 6 of Angular Now Available!
  </aio-notification>
  </mat-toolbar-row>
  <mat-toolbar-row>
  