title: Value of type 'AuthDataResult' has no member 'providerID' Firebase 5.0
body: <p>I have a problem with the newest version of FirebaseAuth 5.0
  this is my code:</p>
  
  <pre><code>func registerUser (withEmail email: String, andPassword password: String, userCreationComplete: @escaping (_ status: Bool, _ error: Error?) -&gt; ()){
      Auth.auth().createUser(withEmail: email, password: password) { (user, error) in
          guard let user = user else{
              userCreationComplete(false, error)
              return
          }
          let userData = ["provider": user.providerID, "email": user.email]
          DataService.instance.createDBUser(uid: user.uid, userData: userData)
          userCreationComplete(true, nil)
      }
  
  }
  </code></pre>
  
  <p>problem is "Value of type 'AuthDataResult' has no value "ProviderID" " But in firebase 4 this method worked. Thanks!</p>