title: ERROR: Failed to resolve: androidx.legacy:legacy-support-v4
body: <p>After migrating to androidx this error kept showing, can anyone help me with it? </p>
  
  <p>Here's part of the build.gradle </p>
  
  <pre><code>
  buildscript {
      repositories {
          google()
          maven {
              url 'https://maven.google.com'
          }
          jcenter()
  
  
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:3.4.2'
  
          // NOTE: Do not place your application dependencies here; they belong
          // in the individual module build.gradle files
      }
  }
  
  allprojects {
      repositories {
          google()
          maven {
              url 'https://maven.google.com'
          }
          jcenter()
  
      }
  }
  </code></pre>
  
  <p>here's the list of dependencies in build.gradle(app)</p>
  
  <pre><code>dependencies {
      implementation fileTree(dir: 'libs', include: ['*.jar'])
      implementation 'androidx.appcompat:appcompat:1.0.2'
      implementation 'com.google.android.gms:play-services-maps:17.0.0'
      implementation 'androidx.legacy:legacy-support-v4'
      //implementation 'androidx.legacy:legacy-support-v13'
      testImplementation 'junit:junit:4.12'
  
      androidTestImplementation 'androidx.test:runner:1.3.0-alpha02'
      androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0-alpha02'
  }
  </code></pre>
  
  <p>this is the single line of error when I try to sync project </p>
  
  <pre><code>ERROR: Failed to resolve: androidx.legacy:legacy-support-v4:
  Affected Modules: app
  </code></pre>