title: Please verify that the package.json has a valid "main" entry
body: <p>Installed bootstrap via npm on my react project
  Importing bootstrap
  <code>import 'bootstrap/dist/css/bootstrap.min.css';</code></p>
  <p>but it outputs an error: <code>Cannot find module 'D:\project\my-app\node_modules\schema-utils\src\index.js'. Please verify that the package.json has a valid &quot;main&quot; entry</code></p>