title: Uncaught RangeError: `options.awareOfUnicodeTokens` must be set to `true` to use `YYYY` In date picker
body: <p>I am using date packer in my demo react project .
  <a href="https://www.npmjs.com/package/react-datepicker" rel="nofollow noreferrer">https://www.npmjs.com/package/react-datepicker</a>
  Every thing is working fine, but I have one issue <code>whenever I remove one text from date value it gives me this error</code></p>
  
  <blockquote>
    <p>Uncaught RangeError: <code>options.awareOfUnicodeTokens</code> must be set to
    <code>true</code> to use <code>YYYY</code> token; see: <a href="https://git.io/fxCyr" rel="nofollow noreferrer">https://git.io/fxCyr</a>
        at throwProtectedError (nk7475yjwl.codesandbox.io/node_modules/react-datepicker/lib/index.js:2211)
        at parse (nk7475yjwl.codesandbox.io/node_modules/react-datepicker/lib/index.js:5733)
        at parseDate (nk7475yjwl.codesandbox.io/node_modules/react-datepicker/lib/index.js:5962)
        at DatePicker._this.handleChange (nk7475yjwl.codesandbox.io/node_modules/react-datepicker/lib/index.js:8536)
        at HTMLUnknownElement.callCallback (react-dom.development.js:145)
        at Object.invokeGuardedCallbackDev (react-dom.development.js:195)
        at invokeGuardedCallback (react-dom.development.js:248)
        at invokeGuardedCallbackAndCatchFirstError (react-dom.development.js:262)
        at executeDispatch (react-dom.development.js:593)
        at executeDispatchesInOrder (react-dom.development.js:615)
        at executeDispatchesAndRelease (react-dom.development.js:713)
        at executeDispatchesAndReleaseTopLevel (react-dom.development.js:724)
        at Array.forEach ()
        at forEachAccumulated (react-dom.development.js:692)
        at runEventsInBatch (react-dom.development.js:855)
        at runExtractedEventsInBatch (react-dom.development.js:864)
        at handleTopLevel (react-dom.development.js:4857)
        at batchedUpdates$1 (react-dom.development.js:17498)
        at batchedUpdates (react-dom.development.js:2189)
        at dispatchEvent (react-dom.development.js:4936)
        at interactiveUpdates$1 (react-dom.development.js:17553)
        at interactiveUpdates (react-dom.development.js:2208)
        at dispatchInteractiveEvent (react-dom.development.js:4913)</p>
  </blockquote>
  
  <p>Steps to produce bug</p>
  
  <ol>
  <li>Run the application.It shows <code>09-Dec-1998</code></li>
  <li>Try to remove <code>8</code> from field or from <code>1998</code>. it shows above error</li>
  </ol>
  
  <p>here is my code</p>
  
  <p><a href="https://codesandbox.io/s/nk7475yjwl" rel="nofollow noreferrer">https://codesandbox.io/s/nk7475yjwl</a></p>
  
  <p>git link
  <a href="https://github.com/Hacker0x01/react-datepicker" rel="nofollow noreferrer">https://github.com/Hacker0x01/react-datepicker</a></p>