title: The library com.google.android.gms:play-services-basement is being requested by various other libraries at [[15.0.1,15.0.1]], but resolves to 11.8.0
body: <p>I would like to add notification with firebase on my app.
  I followed a video on YouTube (<a href="https://www.youtube.com/watch?v=xx7hemn3FY4" rel="noreferrer">https://www.youtube.com/watch?v=xx7hemn3FY4</a>)
  But I have an error when I do the same thing in my flutter project : The library com.google.android.gms:play-services-basement is being requested by various other libraries at [[15.0.1,15.0.1]], but resolves to 11.8.0. Disable the plugin and check your dependencies tree using ./gradlew :app:dependencies.</p>
  
  <p>I tried several things as you can see in comment.</p>
  
  <p>Project gradle :</p>
  
  <pre><code> buildscript {
      repositories {
          google()
          jcenter()
      }
  
  dependencies {
      classpath 'com.android.tools.build:gradle:3.0.1'
  
      classpath 'com.google.gms:google-services:4.0.1'
      //classpath 'com.google.gms:google-services:4.0.0'
  
  }
  }
  
  allprojects {
      repositories {
          google()
          jcenter()
          /*
          maven {
              url "https://maven.google.com" // Google's Maven repository
          }
          */
      }
  }
  
  rootProject.buildDir = '../build'
  subprojects {
      project.buildDir = "${rootProject.buildDir}/${project.name}"
  }
  subprojects {
      project.evaluationDependsOn(':app')
  }
  
  task clean(type: Delete) {
      delete rootProject.buildDir
  }
  
  subprojects {
      project.configurations.all {
          resolutionStrategy.eachDependency { details -&gt;
              if (details.requested.group == 'com.android.support'
                      &amp;&amp; !details.requested.name.contains('multidex') ) {
                  details.useVersion "27.1.0"
              }
  
          }
      }
  }
  </code></pre>
  
  <p>App Gradle :</p>
  
  <pre><code>def localProperties = new Properties()
  def localPropertiesFile = rootProject.file('local.properties')
  if (localPropertiesFile.exists()) {
      localPropertiesFile.withReader('UTF-8') { reader -&gt;
          localProperties.load(reader)
      }
  }
  
  def flutterRoot = localProperties.getProperty('flutter.sdk')
  if (flutterRoot == null) {
      throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
  }
  
  apply plugin: 'com.android.application'
  apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
  
  android {
      compileSdkVersion 27
  
      lintOptions {
          disable 'InvalidPackage'
      }
  
      defaultConfig {
          // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
          applicationId "com.example.weatherapp"
          minSdkVersion 16
          targetSdkVersion 27
          versionCode 1
          versionName "1.0"
          testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
      }
  
      buildTypes {
          release {
              // TODO: Add your own signing config for the release build.
              // Signing with the debug keys for now, so `flutter run --release` works.
              signingConfig signingConfigs.debug
          }
      }
  }
  
  flutter {
      source '../..'
  }
  
  dependencies {
      testImplementation 'junit:junit:4.12'
      androidTestImplementation 'com.android.support.test:runner:1.0.1'
      androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
      //Implementation 'com.google.android.gms:play-services-basement:15.0.1'
      //Implementation 'com.google.firebase:firebase-core:15.0.0'
  }
  
  apply plugin: 'com.google.gms.google-services'
  </code></pre>
  
  <p>But none of these changes works. Do you have an other idea ?</p>