Creating an Ember CLI in-app Addon: how to install npm dependencies?

I have an "in-app" Ember addon in my project's lib directory. The addon has its own dependencies listed in its own package.json file. My project's top level package.json specifies the addon path:

  "ember-addon": {
    "paths": [
      "lib/my-addon-here"
    ]
  }

However, when I run npm install at the project root, it does not install the addon's dependencies.

Is there a way to configure this so that the addon's dependencies are installed when running npm install from the project root?