title: Is it possible to ignore child dependencies in Composer config?
body: <p>When I run composer install, it will install all my "require" and the "require" of the other package.</p>
  
  <p>My composer.json</p>
  
  <pre><code>{
      "name": "my_app",
      "require": {
          "some/package": "0.0.0"
      }
  }
  </code></pre>
  
  <p>The "child" dependency</p>
  
  <pre><code>{
      "name": "some/package",
      "require": {
          "zendframework/zend-mail": "2.4.*@dev",
          "soundasleep/html2text": "~0.2",
          "mpdf/mpdf": "6.0.0",
          "endroid/qrcode": "1.*@dev"
      }
  }
  </code></pre>
  
  <p>I know that it's possible ignore the php extensions, but what about these second require package?</p>