react-native-firebaseui-auth/android/build.gradle

 buildscript {
     repositories {
         google()
         jcenter()
     }

     dependencies {
         classpath 'com.android.tools.build:gradle:3.4.2'
     }
 }

 allprojects {
     repositories {
         google()
         mavenLocal()
         jcenter()
         maven {
             // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm
             url "$rootDir/../node_modules/react-native/android"
         }
     }
 }

apply plugin: 'com.android.library'

android {
    compileSdkVersion 28

    defaultConfig {
        minSdkVersion 16
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
    }
    lintOptions {
        abortOnError false
    }
}

repositories {
    mavenCentral()
    google()
}

dependencies {
    implementation 'com.facebook.react:react-native:+'
    implementation 'com.firebaseui:firebase-ui-auth:6.2.0'

    // Required only if Facebook login support is required
    // Find the latest Facebook SDK releases here: https://goo.gl/Ce5L94
    implementation 'com.facebook.android:facebook-android-sdk:[5,6)'

    // Required only if Twitter login support is required
    // Find the latest Twitter SDK releases here: https://goo.gl/E5wZvQ
    implementation 'com.twitter.sdk.android:twitter-core:3.+'
}