title: "Browser or app may not be secure. Try using a different browser." error with Flutter Firebase Google Login
body: <p>I am using flutter web and firebase authentication to build a web app. For that
  1. Created Firebase app with Google signin as one of the sign in methods.
  2. Added the dependencies as given in <a href="https://github.com/FirebaseExtended/flutterfire/tree/master/packages/firebase_auth/firebase_auth/example" rel="noreferrer">https://github.com/FirebaseExtended/flutterfire/tree/master/packages/firebase_auth/firebase_auth/example</a>
  and <a href="https://dart-pub.mirrors.sjtug.sjtu.edu.cn/packages/firebase_auth_web" rel="noreferrer">https://dart-pub.mirrors.sjtug.sjtu.edu.cn/packages/firebase_auth_web</a>.</p>
  
  <p>When I try to login, the Google sign-in window appears. Once I enter the email address and press enter, it gives the following error. </p>
  
  <blockquote>
    <p>"Couldn't sign you in This browser or app may not be secure. Try using
    a different browser. If you’re already using a supported browser, you
    can refresh your screen and try again to sign in."</p>
  </blockquote>
  
  <p>I used Chrome browser.
  What should I do to make my app more secure ? For android, we had the option of using SHA keys to encrypt the connection. Do we need to do something similar for web ?</p>