build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {

    ext {
        kotlinVersion = '1.2.50'
    }

    repositories {
        google()
        jcenter()
        maven {
            url 'https://jitpack.io'
        }
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.4'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlinVersion}"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

configurations.all {
    // check for updates every build
    resolutionStrategy.cacheChangingModulesFor 0, 'seconds'
}

allprojects {
    repositories {
        google()
        jcenter()
        maven {
            url 'https://oss.sonatype.org/content/repositories/snapshots'
        }
        maven {
            url 'https://jitpack.io'
        }
        maven { url 'https://maven.google.com' }
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}