title: Dependency failing: io.grpc:grpc-auth:1.13.1 -> io.grpc:grpc-core@[1.13.1], but grpc-core version was 1.16.1
body: <p>I'm developing an app that uses Dialogflow and firestore at the same time, but I don't know why, it shows me this error:</p>
  
  <pre><code>    ERROR: In project 'app' a resolved Google Play services library dependency depends on another at an exact version (e.g. "[1.13.
  1]", but isn't being resolved to that version. Behavior exhibited by the library will be unknown.
  
  Dependency failing: io.grpc:grpc-auth:1.13.1 -&gt; io.grpc:grpc-core@[1.13.1], but grpc-core version was 1.16.1.
  
  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 io.grpc:grpc-netty-shaded@1.13.1
  -- Project 'app' depends onto com.google.cloud:google-cloud-core-grpc@1.49.0
  -- Project 'app' depends onto io.grpc:grpc-protobuf-lite@1.16.1
  -- Project 'app' depends onto io.grpc:grpc-core@1.16.1
  -- Project 'app' depends onto com.google.firebase:firebase-firestore@17.1.5
  -- Project 'app' depends onto com.google.api:gax-grpc@1.32.0
  -- Project 'app' depends onto io.grpc:grpc-protobuf@1.13.1
  -- Project 'app' depends onto io.grpc:grpc-android@1.16.1
  -- Project 'app' depends onto io.grpc:grpc-okhttp@1.16.1
  -- Project 'app' depends onto com.google.cloud:google-cloud-dialogflow@0.67.0-alpha
  -- Project 'app' depends onto io.grpc:grpc-auth@1.13.1
  -- Project 'app' depends onto io.grpc:grpc-okhttp@1.13.1
  -- Project 'app' depends onto io.grpc:grpc-stub@1.16.1
  
  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.
  </code></pre>
  
  <p>This happens when I add the "implementation 'com.google.firebase:firebase-firestore:17.1.5'" libarary. I have this build.gradle:</p>
  
  <pre><code>    apply plugin: 'com.android.application'
  
  android {
      compileSdkVersion 28
      defaultConfig {
          applicationId "com.example.appv9"
          minSdkVersion 21
          targetSdkVersion 28
          versionCode 1
          versionName "1.0"
          testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
      }
  
      compileOptions {
          sourceCompatibility JavaVersion.VERSION_1_8
          targetCompatibility JavaVersion.VERSION_1_8
      }
      // Java V2
      packagingOptions {
          exclude 'META-INF/LICENSE'
          exclude 'META-INF/DEPENDENCIES'
          exclude 'META-INF/INDEX.LIST'
      }
  }
  
  dependencies {
      implementation fileTree(dir: 'libs', include: ['*.jar'])
      implementation 'com.android.support:appcompat-v7:28.0.0'
      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'
  
      // Dialogflow SDK dependencies
      implementation 'ai.api:sdk:2.0.7@aar'
      implementation 'ai.api:libai:1.6.12'
  
      // Java V2
      implementation 'com.google.cloud:google-cloud-dialogflow:0.67.0-alpha'
      // for Remote Procedure Call to avoid "No functional channel service provider found" error while creating SessionsClient
      implementation 'io.grpc:grpc-okhttp:1.13.1'
  
      implementation 'com.google.firebase:firebase-core:16.0.6'
      implementation 'com.google.firebase:firebase-auth:16.1.0'
      implementation 'com.google.firebase:firebase-firestore:17.1.5' 
      // Google Sign In SDK (only required for Google Sign In)
      implementation 'com.google.android.gms:play-services-auth:16.0.1'
  
  }
  
  apply plugin: 'com.google.gms.google-services'
  </code></pre>
  
  <p>And this one: </p>
  
  <pre><code>// Top-level build file where you can add configuration options common to all sub-projects/modules.
  
  
  buildscript {
  
      repositories {
          google()
          jcenter()
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:3.3.1'
          classpath 'com.google.gms:google-services:4.2.0'
  
          // NOTE: Do not place your application dependencies here; they belong
          // in the individual module build.gradle files
      }
  }
  
  allprojects {
      repositories {
          google()
          jcenter()
      }
  }
  
  task clean(type: Delete) {
      delete rootProject.buildDir
  }
  </code></pre>
  
  <p>I don't know how to solve it because as you can see above my grpc is in 1.13.1 version, can anyone help me? Thanks a lot! </p>