自动集成极光推送的时候 jcenter为什么没有自动导入到AndroidManifest.xml

Error:Execution failed for task ':app:processDebugManifest'.
> Manifest merger failed : Attribute meta-data#JPUSH_CHANNEL@value at AndroidManifest.xml requires a placeholder substitution but no value for <JPUSH_CHANNEL> is provided.

提示这个报错 ，请求大神解答下 谢谢了