title: Value of type 'GIDSignIn' has no member 'signInSilently'
body: <p>What is this error, please guide no material found anywhere on google so far. Below is my code which is giving error:</p>
  
  <pre><code>if GIDSignIn.sharedInstance().hasAuthInKeychain() == false {
                 GIDSignIn.sharedInstance().signIn()
             } else {
                 if let user = GIDSignIn.sharedInstance().currentUser {
                     service.authorizer = user.authentication.fetcherAuthorizer()
                     fetchEvents()
                 } else {
                     GIDSignIn.sharedInstance().signInSilently()
                 }
             }
  </code></pre>
  
  <p>Two errors coming:</p>
  
  <pre><code>Value of type 'GIDSignIn' has no member 'hasAuthInKeychain'
  Value of type 'GIDSignIn' has no member 'signInSilently'
  </code></pre>