Merging the 6.3.0 release into master (#3217)

* Update versions for Release 6.3.0

* Revert "Raise exception when log into Facebook using OAuth.  (#3138)" (#3208) (#3209)

This reverts commit 393d060710.

FirebaseCore.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = 'FirebaseCore'
-  s.version          = '6.0.2'
+  s.version          = '6.0.3'
   s.summary          = 'Firebase Core for iOS (plus community support for macOS and tvOS)'
 
   s.description      = <<-DESC
@@ -33,7 +33,7 @@ Firebase Core includes FIRApp and FIROptions which provide central configuration
   s.pod_target_xcconfig = {
     'GCC_C_LANGUAGE_STANDARD' => 'c99',
     'GCC_PREPROCESSOR_DEFINITIONS' =>
-      'FIRCore_VERSION=' + s.version.to_s + ' Firebase_VERSION=6.2.0',
+      'FIRCore_VERSION=' + s.version.to_s + ' Firebase_VERSION=6.3.0',
     'OTHER_CFLAGS' => '-fno-autolink'
   }
   s.test_spec 'unit' do |unit_tests|