title: Error: unable to find directory entry in pubspec.yaml
body: <p>I am trying to add assets from an external package in my flutter application
  as mentioned here: <a href="https://flutter.dev/docs/development/ui/assets-and-images#bundling-of-package-assets" rel="nofollow noreferrer">https://flutter.dev/docs/development/ui/assets-and-images#bundling-of-package-assets</a></p>
  
  <p>I am getting this <code>Error: unable to find directory entry in pubspec.yaml /project/location/&lt;project_name&gt;/packages</code> even for adding this simple entry which cant be null.</p>
  
  <pre><code>  assets:
      - packages/
  </code></pre>