title: Could not find plugin "proposal-numeric-separator"
body: <p>How to fix <code>Could not find plugin "proposal-numeric-separator"</code>, I get this error when I try to build my React application, I have not ejected the application yet:</p>
  
  <pre><code>./src/index.js
  Error: [BABEL] /home/pc/Downloads/project/src/index.js: Could not find plugin "proposal-numeric-separator". Ensure there is an entry in ./available-plugins.js for it. (While processing: "/home/pc/Downloads/project/node_modules/babel-preset-react-app/index.js$0")
      at Array.map (&lt;anonymous&gt;)
      at Generator.next (&lt;anonymous&gt;)
      at Generator.next (&lt;anonymous&gt;)
  
  
  error Command failed with exit code 1.
  info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
  </code></pre>
  
  <p>I have tried to download Babel and the dependency Proposal Numeric Separator, remove the Node Modules, clean the Yarn cache; but nothing worked.</p>
  
  <p>I'm using Yarn 1.22.4 and Node 13.11.0, but I have also tried with NPM 6.13.7.</p>