title: Could not find plugin "proposal-class-properties"
body: <p>I am working on react project. It was working properly. But now whenever I start npm. It gives me error:</p>
  <pre><code>$ react-scripts start
  i ｢wds｣: Project is running at http://192.168.18.45/
  i ｢wds｣: webpack output is served from
  i ｢wds｣: Content not from webpack is served from C:\xampp\htdocs\SkyHi\Staah\staah-instant-site\public
  i ｢wds｣: 404s will fallback to /
  Starting the development server...
  Failed to compile.
  
  ./node_modules/@fortawesome/fontawesome-svg-core/index.es.js
  Error: [BABEL] C:\xampp\htdocs\SkyHi\Staah\staah-instant-site\node_modules\@fortawesome\fontawesome-svg-core\index.es.js: Could not find plugin &quot;proposal-class-properties&quot;. Ensure there is an entry in ./available-plugins.js for it. (While processing: &quot;C:\\xampp\\htdocs\\SkyHi\\Staah\\staah-instant-site\\node_modules\\babel-preset-react-app\\dependencies.js$0&quot;)
      at Array.map (&lt;anonymous&gt;)
      at Generator.next (&lt;anonymous&gt;)
      at Generator.next (&lt;anonymous&gt;)
  </code></pre>
  <p>I am using <code>yarn</code>.</p>
  <p>How can I solve this error?</p>