title: QuerySnapshot.docChanges has been changed from a property into a method
body: <p>I keep getting this message:</p>
  
  <blockquote>
    <p>QuerySnapshot.docChanges has been changed from a property into a method, so usages like "querySnapshot.docChanges" should become "querySnapshot.docChanges()"</p>
  </blockquote>
  
  <p>I am using "firebase": "^5.3.0"</p>
  
  <p>In my package.json</p>