title: CocoaPods could not find compatible versions for pod "GoogleSignIn": In Podfile: GoogleSignIn
body: <p>How to solve this error ?</p>
  <p>My Podfile looks like this :</p>
  <pre><code>  pod 'Firebase/Core'
    pod 'Firebase/Auth'
    pod 'GoogleSignIn'
  end
  </code></pre>