Update podspec for 6.0.0 release

Change-Id: I5c4e596bcb493417a39c5f0f342ccd69b31e5c7a

Author: morganchen12

FirebaseUI.podspec

@@ -1,11 +1,10 @@
 Pod::Spec.new do |s|
   s.name         = 'FirebaseUI'
-  s.version      = '5.2.2'
+  s.version      = '6.0.0'
   s.summary      = 'UI binding libraries for Firebase.'
   s.homepage     = 'https://github.com/firebase/FirebaseUI-iOS'
   s.license      = { :type => 'Apache 2.0', :file => 'LICENSE' }
-  # s.source       = { :git => 'https://github.com/firebase/FirebaseUI-iOS.git', :tag => 'v' + s.version.to_s }
-  s.source       = { :git => 'https://github.com/firebase/FirebaseUI-iOS.git', :branch => 'restructure' }
+  s.source       = { :git => 'https://github.com/firebase/FirebaseUI-iOS.git', :tag => 'v' + s.version.to_s }
   s.author       = 'Firebase'
   s.platform = :ios
   s.ios.deployment_target = '9.0'
@@ -107,7 +106,7 @@ Pod::Spec.new do |s|
     facebook.public_header_files = 'FacebookAuth/FirebaseFacebookAuthUI/*.h'
     facebook.source_files = 'FacebookAuth/FirebaseFacebookAuthUI/*.{h,m}'
     facebook.dependency 'FirebaseUI/Auth'
-    facebook.dependency 'FBSDKLoginKit', '~> 4.0'
+    facebook.dependency 'FBSDKLoginKit', '~> 4.39'
     facebook.resource_bundle = {
       'FirebaseFacebookAuthUI' => ['FacebookAuth/FirebaseFacebookAuthUI/**/*.{png,lproj}']
     }