title: React-Native cannot find symbol after upgrade to 0.60
body: <p>I try to upgrade my react-native app 0.59.4 to 0.60.0.</p>
  
  <p>I use <a href="https://react-native-community.github.io/upgrade-helper/?from=0.59.4&amp;to=0.60.0" rel="noreferrer">this link</a> as reference to upgrade all native files. But when I try to run my app on an Android device, I've got this error :</p>
  
  <pre><code>Deprecated Gradle features were used in this build, making it incompatible with Gradle 6.0.
  Use '--warning-mode all' to show the individual deprecation warnings.
  See https://docs.gradle.org/5.4.1/userguide/command_line_interface.html#sec:command_line_warnings
  12 actionable tasks: 4 executed, 8 up-to-date
  /home/stephane/Project/youtube-audio-player/android/app/src/main/java/com/youtubeaudioplayer/MainApplication.java:5: error: cannot find symbol
  import com.facebook.react.PackageList;
                           ^
    symbol:   class PackageList
    location: package com.facebook.react
  /home/stephane/Project/youtube-audio-player/android/app/src/main/java/com/youtubeaudioplayer/MainApplication.java:6: error: cannot find symbol
  import com.facebook.react.ReactApplication;
                           ^
    symbol:   class ReactApplication
    location: package com.facebook.react
  /home/stephane/Project/youtube-audio-player/android/app/src/main/java/com/youtubeaudioplayer/MainApplication.java:7: error: cannot find symbol
  import com.facebook.react.ReactNativeHost;
  </code></pre>
  
  <p>Did anyone already upgrade to 0.60 version successfully?</p>