title: Formik - "dirty" gets applied to all instances with the same custom component
body: <p><strong>Current Behavior</strong></p>
  
  <p>When I create a custom input component and try to add a className based on if the input is "dirty" or not, the class gets applied to all the inputs that use this component.</p>
  
  <p>Here's a simple example I created ...
  <a href="https://codesandbox.io/s/hello-world-h60hj" rel="nofollow noreferrer">https://codesandbox.io/s/hello-world-h60hj</a></p>
  
  <p>You'll notice that both inputs use the same custom component "InputComponent", and when you start typing in any one of them, the class gets applied to both of them.</p>
  
  <p>I think the "isValid" is also behaving the same way.</p>
  
  <p><strong>Expected behavior</strong></p>
  
  <p>The class should be applied to only the dirty input that I'm typing inside.</p>
  
  <p>Am I doing something wrong here?</p>