unityエラー Google.JarResolver.ResolutionException: Cannot find candidate artifact

unityのgoogle Game serviceマルチプレイヤーを最新にしたところ以下のエラーが発生
Google.JarResolver.ResolutionException: Cannot find candidate artifact for com.google.android.gms:play-services-games:8.4+
  at Google.JarResolver.PlayServicesSupport.DependOn (System.String group, System.String artifact, System.String version) [0x00000] in <filename unknown>:0 
  at GooglePlayGames.Editor.GPGSDependencies..cctor () [0x00024] in /Users/yuuki/Downloads/play-games-plugin-for-unity-master/samples/YSGameService/Assets/GooglePlayGames/Editor/GPGSDependencies.cs:46 
UnityEditor.EditorAssemblies:SetLoadedEditorAssemblies(Assembly[])

解決方法

以下を更新する。
AndroidSDKマネージャー＞Extras

• Android Support Repository
• Android Support Library
• Google Play Services
• Google Repository

要は最新版の組み合わせが必要らしい。