title: Use of undeclared type 'UNUserNotificationCenter'
body: <p>i want to show banner of  push notification when app is in foreground. And i implementing this method to show notification: </p>
  
  <pre><code>func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -&gt; Void)
          {
              completionHandler([.alert, .badge, .sound])
          }
  </code></pre>
  
  <p>but this error received Use of undeclared type 'UNUserNotificationCenter'
  <a href="https://i.stack.imgur.com/xF6tl.png" rel="noreferrer"><img src="https://i.stack.imgur.com/xF6tl.png" alt="enter image description here"></a></p>