title: date-fns isToday() returning a confusing value
body: <p>I am confused about the output of the date-fns <code>isToday()</code> function.</p>
  
  <p>Running <code>new Date()</code> I currently get <code>2019-09-06T20:12:40.737Z</code></p>
  
  <p>I am running <code>2019-09-06T00:00:00.000Z</code> through <code>isToday()</code> and it is returning false.</p>
  
  <p>I am also confused because when I stringify my date it return yesterday's date.</p>
  
  <pre><code>cost isToday = require('date-fns/isToday')
  
  myDate === // 2019-09-06T00:00:00.000Z
  
  console.log(new Date())
  // 2019-09-06T20:12:40.737Z
  
  console.log(isToday(myDate))
  // false
  
  console.log(myDate.toString())
  // Thu Sep 05 2019 18:00:00 GMT-0600 (Mountain Daylight Time)
  
  </code></pre>
  
  <p>Is this a time zone thing? Am I misunderstanding the way that javascript dates are stored? Or is this a date-fns issue?</p>