title: Use destinationDir in gradle custom plugin
body: <p>I have a gradle task where I create a sourceZip of my project and as a result a zip file Is created. I want that zip to be created in a specific folder source. In the task, I write it as </p>
  
  <pre><code>destinationDir = file('/source')
  </code></pre>
  
  <p>I cant use this directly in custom plugin as it gives error 'Gradle DSL method not found/; file()'
  Is there any way we can use this in custom plugin</p>