Could not find method maven() for arguments [build_48jju0eu9q7aafln0yi713a7l$_run_closure1$_closure4@3cb5a1fe]

Question

My build.gradle

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

 buildscript {
  repositories {
    jcenter()
    google()
  }
  dependencies {
    classpath 'com.android.tools.build:gradle:3.5.0'

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

allprojects {
  repositories {
    jcenter()
  }
  maven {
    url "https://maven.google.com"

  }
}     

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

**My error code is

Could not find method maven() for arguments [build_48jju0eu9q7aafln0yi713a7l$_run_closure1$_closure4@3cb5a1fe] on root project 'androidtest2' of type org.gradle.api.Project.**

and https://github.com/ujink/Android-HC06-Arduino

this program