title: setFieldsValue does not re-render form value
body: <p>This is a silly example. Let's say I have 2 items in the form (gender and age). If age &gt; 18 then gender should be boy else gender should be a girl.</p>
  <p>If I change the age by inputting a new value to the number input, everything works as expected. However, if I change the age by clicking on the button, my app does not work. Could you guys help me on this? I would like the gender is updated as well when clicking on the button</p>
  <p><a href="https://codesandbox.io/s/upbeat-montalcini-wlt61?file=/src/App.js" rel="nofollow noreferrer">https://codesandbox.io/s/upbeat-montalcini-wlt61?file=/src/App.js</a></p>
  <p>Steps to reproduce</p>
  <p>Click on button</p>
  <p>What is expected?
  Age is changed to 25, gender is changed to Boy</p>
  <p>What is actually happening?
  Age is changed to 25, gender is not changed</p>