title: How to make the gradle ShadowJar task also create sources and javadoc of its children?
body: <p>I have a gradle project with 8 child projects and a configured shadowjar task to create an "all" jar. The toplevel project is setup to have dependencies to all its children, this tells shadowjar what to include:</p>
  
  <pre><code>project(':') {
      dependencies {
          compile project(':jfxtras-agenda')
          compile project(':jfxtras-common')
          compile project(':jfxtras-controls')
          compile project(':jfxtras-icalendarfx')
          compile project(':jfxtras-icalendaragenda')
          compile project(':jfxtras-menu')
          compile project(':jfxtras-gauge-linear')
          compile project(':jfxtras-font-roboto')
      }
  }
  
  shadowJar {
     classifier = null // do not append "-all", so the generated shadow jar replaces the existing jfxtras-all.jar (instead of generating jfxtras-all-all.jar)
  }
  </code></pre>
  
  <p>This works fine, but maven central is refusing the all jar, because it does not have an associated sources and javadocs jar. </p>
  
  <p>How do I tell gradle to also generate the sources and javadoc? ShadowJar's documentation says it should do this by default.</p>