title: Invalid Option: corejs is not a valid top-level option
body: <p>I built react project with webpack and babel.</p>
  
  <p>It worked well.</p>
  
  <p>But, today I got some error below.</p>
  
  <pre><code>ERROR in ./index.js
  Module build failed (from ./node_modules/babel-loader/lib/index.js):
  Error: [BABEL] /home/rpf5573/react-discovery-v2/src/admin/admin-client/index.js: Invalid Option: corejs is not a valid top-level option.
          Maybe you meant to use 'targets'? (While processing: "/home/rpf5573/react-discovery-v2/src/admin/admin-client/node_modules/@babel/preset-env/lib/index.js")
      at validateTopLevelOptions (/home/rpf5573/react-discovery-v2/src/admin/admin-client/node_modules/@babel/preset-env/lib/normalize-options.js:49:13)
      at normalizeOptions (/home/rpf5573/react-discovery-v2/src/admin/admin-client/node_modules/@babel/preset-env/lib/normalize-options.js:160:3)
      at _default (/home/rpf5573/react-discovery-v2/src/admin/admin-client/node_modules/@babel/preset-env/lib/index.js:168:37)
    ....
  error Command failed with exit code 2.
  </code></pre>
  
  <p>And this is my <code>admin-client/.babelrc</code></p>
  
  <pre><code>module.exports = {
    compact: true,
    presets: [
      [
        "@babel/preset-env",
        {
          modules: false,
          targets: {
            browsers: ["since 2015"]
          },
          useBuiltIns: "usage",
          corejs: "2"
        }
      ],
      "@babel/preset-react"
    ],
    plugins: [
      "@babel/plugin-proposal-class-properties"
    ]
  }
  </code></pre>
  
  <p>What did I wrong ?</p>
  
  <p>What should I do ?</p>