title: Unable to find the mojo 'generate-sources'
body: <p>When I try to install playn, I get that :</p>
  
  <pre><code>[INFO] ------------------------------------------------------------------------
  [INFO] Building PlayN Tests Android
  [INFO]    task-segment: [install]
  [INFO] ------------------------------------------------------------------------
  [INFO] [enforcer:enforce {execution: enforce-maven}]
  [INFO] ------------------------------------------------------------------------
  [ERROR] BUILD ERROR
  [INFO] ------------------------------------------------------------------------
  [INFO] Internal error in the plugin manager executing goal 'com.jayway.maven.plugins.android.generation2:android-maven-plugin:3.1.1:generate-sources': Unable to find the mojo 'generate-sources' (or one of its required components) in the plugin 'com.jayway.maven.plugins.android.generation2:android-maven-plugin'
  Component descriptor cannot be found in the component repository: org.sonatype.aether.RepositorySystem.
  </code></pre>