颤振cloud_functions和cloud_firestore，firebase_database，firebase_storage无法同时在pubspec.yaml中打开，否则将报告错误。
firebase_core: ^0.2.5
cloud_functions: ^0.0.4
cloud_firestore: ^0.8.0
firebase_auth: ^0.5.20
firebase_database: ^1.0.4
firebase_storage: ^1.0.2
Xcode的输出：
=== BUILD TARGET cloud_functions OF PROJECT Pods WITH CONFIGURATION Debug ===
/Users/mars/development/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-0.5.20/ios/Classes/FirebaseAuthPlugin.m:79:21: warning: 'signInWithCredential:completion:' is deprecated: Please use signInAndRetrieveDataWithCredential:completion: for Objective-C or signInAndRetrieveData(with:completion:) for Swift instead. [-Wdeprecated-declarations]
[[FIRAuth auth] signInWithCredential:credential