title: In project 'app' a resolved Google Play services library dependency depends on another at an exact version
body: <p>Trying to create a simple app with FireStore and Google Authentication. Having problem with the gradle:</p>
  
  <blockquote>
    <p>In project 'app' a resolved Google Play services library dependency
    depends on another at an exact version (e.g. "[15.0. 1]", but isn't
    being resolved to that version. Behavior exhibited by the library will
    be unknown.</p>
    
    <p>Dependency failing: com.google.android.gms:play-services-flags:15.0.1
    -> com.google.android.gms:play-services-basement@[
    15.0.1], but play-services-basement version was 16.0.1.</p>
    
    <p>The following dependencies are project dependencies that are direct or
    have transitive dependencies that lead to the art ifact with the
    issue.
    -- Project 'app' depends onto com.google.firebase:firebase-firestore@17.1.5
    -- Project 'app' depends onto com.firebaseui:firebase-ui-auth@4.2.0</p>
    
    <p>For extended debugging info execute Gradle from the command line with
    ./gradlew --info :app:assembleDebug to see the dep endency paths to
    the artifact. This error message came from the google-services Gradle
    plugin, report issues at https://
    github.com/google/play-services-plugins and disable by adding
    "googleServices { disableVersionCheck = false }" to your b uild.gradle
    file.</p>
  </blockquote>
  
  <pre><code>    apply plugin: 'com.android.application'
  
      android {
          compileSdkVersion 27
          defaultConfig {
              applicationId "myapp.com"
              minSdkVersion 19
              targetSdkVersion 27
              versionCode 11
              versionName "1.1"
              testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
              multiDexEnabled true
          }
          buildTypes {
              release {
                  minifyEnabled false
                  proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
              }
          }
      }
  
      dependencies {
          implementation fileTree(dir: 'libs', include: ['*.jar'])
          implementation 'com.android.support:appcompat-v7:27.1.1'
          implementation 'com.android.support.constraint:constraint-layout:1.1.3'
          testImplementation 'junit:junit:4.12'
          androidTestImplementation 'com.android.support.test:runner:1.0.2'
          androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
          implementation 'com.google.firebase:firebase-firestore:17.1.5'
  
          implementation 'com.firebaseui:firebase-ui-auth:4.2.0'
  
      }
  
      apply plugin: 'com.google.gms.google-services'
      com.google.gms.googleservices.GoogleServicesPlugin
  </code></pre>
  
  <p>Project gradle:</p>
  
  <pre><code>buildscript {
  
      repositories {
          google()
          jcenter()
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:3.2.1'
  
          classpath 'com.google.gms:google-services:4.2.0'
  
      }
  }
  </code></pre>
  
  <p>Can somebody help me?</p>