title: Command `yarn add react-native --exact` failed
body: <p>I tryed to create new project but this happen , I update the core as they said here <a href="https://stackoverflow.com/questions/55606841/how-to-update-core-js-to-core-js3-dependency">How to update core-js to core-js@3 dependency?</a>
   but also no thing help me
  I use windows 10, what should I do ?</p>
  
  <pre><code>c:\Users\alothman\Desktop&gt;npx react-native init travelApp
  This will walk you through creating a new React Native project in c:\Users\alothman\Desktop\travelApp
  Using yarn v1.21.1
  Installing react-native...
  yarn add v1.21.1
  info No lockfile found.
  [1/4] Resolving packages...
  warning react-native &gt; fbjs &gt; core-js@2.6.11: core-js@&lt;3 is no longer maintained and not recommended for usage due to the number of issues. Please, upgrade your dependencies to the actual version of core-js@3.
  warning react-native &gt; create-react-class &gt; fbjs &gt; core-js@1.2.7: core-js@&lt;3 is no longer maintained and not recommended for usage due to the number of issues. Please, upgrade your dependencies to the actual version of core-js@3.
  warning react-native &gt; fbjs-scripts &gt; core-js@2.6.11: core-js@&lt;3 is no longer maintained and not recommended for usage due to the number of issues. Please, upgrade your dependencies to the actual version of core-js@3.
  warning react-native &gt; metro-babel-register &gt; core-js@2.6.11: core-js@&lt;3 is no longer maintained and not recommended for usage due to the number of issues. Please, upgrade your dependencies to the actual version of core-js@3.
  [2/4] Fetching packages...
  error An unexpected error occurred: "C:\\Users\\alothman\\AppData\\Local\\Yarn\\Cache\\v6\\npm-@babel-runtime-7.7.7-194769ca8d6d7790ec23605af9ee3e42a0aa79cf-integrity\\node_modules\\@babel\\runtime\\.yarn-metadata.json: Unexpected token \u0000 in JSON at position 0".
  info If you think this is a bug, please open a bug report with the information provided in "c:\\Users\\alothman\\Desktop\\travelApp\\yarn-error.log".
  info Visit https://yarnpkg.com/en/docs/cli/add for documentation about this command.
  { Error: Command failed: yarn add react-native --exact
      at checkExecSyncError (child_process.js:629:11)
      at execSync (child_process.js:666:13)
      at run (C:\Users\alothman\AppData\Roaming\npm\node_modules\react-native-cli\index.js:294:5)
      at createProject (C:\Users\alothman\AppData\Roaming\npm\node_modules\react-native-cli\index.js:249:3)
      at init (C:\Users\alothman\AppData\Roaming\npm\node_modules\react-native-cli\index.js:200:5)
      at Object.&lt;anonymous&gt; (C:\Users\alothman\AppData\Roaming\npm\node_modules\react-native-cli\index.js:153:7)
      at Module._compile (internal/modules/cjs/loader.js:778:30)
      at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
      at Module.load (internal/modules/cjs/loader.js:653:32)
      at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
    status: 1,
    signal: null,
    output: [ null, null, null ],
    pid: 5380,
    stdout: null,
    stderr: null }
  Command `yarn add react-native --exact` failed.
  </code></pre>