当project-build.gradle变为3.1.3后，配置如下：

dependencies {
   classpath 'com.android.tools.build:gradle:3.1.3'
   classpath 'com.jakewharton:butterknife-gradle-plugin:8.8.1'


   classpath 'com.jakewharton:butterknife-gradle-plugin:9.0.0-SNAPSHOT'

整个项目就跑不起来了，出现：

Unable to find method 'com.android.build.gradle.api.BaseVariant.getOutputs()Ljava/util/List;'.

Possible causes for this unexpected error include:<ul><li>Gradle's dependency cache may be corrupt (this sometimes occurs after a network connection timeout.)

Re-download dependencies and sync project (requires network)</li><li>The state of a Gradle build process (daemon) may be corrupt. Stopping all Gradle daemons may solve this problem.

Stop Gradle build processes (requires restart)</li><li>Your project may be using a third-party plugin which is not compatible with the other plugins in the project or the version of Gradle requested by the project.</li></ul>In the case of corrupt Gradle processes, you can also try closing the IDE and then killing all Java processes.

老师能否提供一份这个环境下可以运行的代码？