title: lot of warnings after installing facebook SDK on my iOS app
body: <p>i am trying to install facebook SDK on my iOS app in order to make social login using facebook account. but after installing through cocoapods, it gives me a lot of warning message. I am using Xcode 9.2. here is the code on my podfile when installing using cocoapods</p>
  
  <pre><code># Uncomment the next line to define a global platform for your project
  platform :ios, '9.0'
  
  target 'facebook login firebase' do
    # Comment the next line if you're not using Swift and don't want to use dynamic frameworks
    use_frameworks!
  
    # Pods for facebook login firebase
  
  pod 'Bolts'
  pod 'FBSDKCoreKit'
  pod 'FBSDKShareKit'
  pod 'FBSDKLoginKit'
  
  end
  </code></pre>
  
  <p>and here is the screenshot of the warning
  <a href="https://i.stack.imgur.com/ycRUJ.png" rel="noreferrer"><img src="https://i.stack.imgur.com/ycRUJ.png" alt="enter image description here"></a>
  <a href="https://ibb.co/kx5fCR" rel="noreferrer">https://ibb.co/kx5fCR</a> 
  (here is the link in case the image doesn't appear)</p>
  
  <p><a href="https://developers.facebook.com/docs/ios/getting-started" rel="noreferrer">https://developers.facebook.com/docs/ios/getting-started</a>
  i am in the step 4 of that documentation, but the warnings show up. so what went wrong in here? do i miss something?</p>