title: How to implement ringing (incoming call) notification in Ionic 5
body: <p>I have a voice call project in my ionic 5 / Angular app.
  I am using Firebase Cloud Messaging as my notification service for Android and IOS.</p>
  <p>I want to implement ringtone or ringing notifications for the application, like Microsoft Teams or other messaging app on incoming calls.</p>
  <p>Is there any native plugin or tools to support this feature? Or should I create a native functions inside my cordova platform?</p>
  <p>I am currently tinkering with fcm notifications using vibrating pattern, sound, and some properties. Is it right to use default normal notification as an incoming call notification?</p>
  <p>Thank you in advance.</p>