I can't find allproject

sorry newbie here i want use TextFieldBoxes

the installation need to find :

allprojects {
    repositories {
      ...
      maven { url 'https://jitpack.io' }
    }
}

why i cant find allproject, here my build.gradle :

  buildscript {
    repositories {
        google()
        mavenCentral()
    }
    dependencies {
        classpath "com.android.tools.build:gradle:7.0.2"

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

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

help :D