Bump AppAuth dependency to 1.2.0

Author: Mitch528

react-native-app-auth.podspec

@@ -14,5 +14,5 @@ Pod::Spec.new do |s|
   s.source_files  = 'ios/**/*.{h,m}'
   s.requires_arc = true
   s.dependency 'React'
-  s.dependency 'AppAuth', '1.0.0'
+  s.dependency 'AppAuth', '1.2.0'
 end