Add maven and bintray plugin to your root gradle file build script dependencies(root project gradle.build)
classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.7'
classpath 'com.github.dcendents:android-maven-gradle-plugin:1.4.1'
Your build scipt dependencies should look like this
dependencies {
classpath 'com.android.tools.build:gradle:3.0.1'
// Required plugins added to classpath to facilitate pushing to Jcenter/Bintray
classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.7'
classpath 'com.github.dcendents:android-maven-gradle-plugin:1.4.1'
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
}