title: 'FacebookCore' does not specify a Swift version and none of the targets ('AppName') integrating it have the 'SWIFT_VERSION' attribute set
body: <p>i am getting this error when i trying to install pod.</p>
  <p>Error:-
  ```['FacebookCore' does not specify a Swift version and none of the targets ('AppName') integrating it have the <code>SWIFT_VERSION</code> attribute set. Please contact the author or set the <code>SWIFT_VERSION</code> attribute in at least one of the targets that integrate this pod.</p>
  <ul>
  <li>'FacebookShare' does not specify a Swift version and none of the targets ('AppName') integrating it have the <code>SWIFT_VERSION</code> attribute set. Please contact the author or set the <code>SWIFT_VERSION</code> attribute in at least one of the targets that integrate this pod.]```</li>
  </ul>
  <p>Here is my pod file detail:-</p>
  <pre><code>   use_frameworks!
  
    # Pods for AppName
    pod 'AppsFlyerFramework'
    pod 'FacebookShare'
    pod 'Firebase/Analytics'
    pod 'Firebase/Crashlytics'
  end
  
  using xcode 11.3.1 and not using any swift class
  </code></pre>