将AndroidStudio升级为3.6版本，与butterknife插件会发生冲突，不兼容的问题，报错信息如下所示：
ERROR: Unable to find method 'com.android.build.gradle.api.BaseVariant.getOutputs()Ljava/util/List;'. Possible causes for this unexpected error include: Gradle's dependency cache may be corrupt (this sometimes occurs after a network connection timeout.) Re-download dependencies and sync project (requires network) The state of a Gradle build process (daemon) may be corrupt
解决办法：将butterknife的版本8.8.1降到8.4.0就可以了
