title: Value of type 'GIDSignIn' has no member 'presentingViewController'
body: <p>I am learning the google sign-in to app with GoogleSignIn SDK (Installed with cocoapods). I did not specify version in pod file, its automatically installed GoogleSignIn (4.4.0). Going Through the documentation <a href="https://developers.google.com/identity/sign-in/ios/sign-in?ver=swift" rel="noreferrer">here</a>.
  According to documentation, To add sign in button we have to write </p>
  
  <pre><code>GIDSignIn.sharedInstance()?.presentingViewController = self
  
    // Automatically sign in the user.
    GIDSignIn.sharedInstance()?.restorePreviousSignIn()
  </code></pre>
  
  <p>but in latest Xcode Version 10.3 (10G8) i am getting error</p>
  
  <pre><code>Value of type 'GIDSignIn' has no member 'presentingViewController'
  Value of type 'GIDSignIn' has no member 'restorePreviousSignIn'
  </code></pre>
  
  <p>I tried to search about the updated version for this but unfortunately not found. Kindly help me out to integrate GoogleSignIn</p>