`dirtySinceLastSubmit` doesn't update when fields push/remove

### Are you submitting a **bug report** or a **feature request**?

Bug report

### What is the current behavior?

`meta.dirtySinceLastSubmit` is not updated after `fields.push` or `fields.remove` call. Though not tested yet, I doubt the same problem exists in other fields methods.

### What is the expected behavior?
(See sandbox link)
1. click "Submit" button
2. click "Add a habit" button

Expect the `habits` field array to have `meta.dirtySinceLastSubmit === true`

### Sandbox Link
https://codesandbox.io/s/upbeat-pine-23rt4

### What's your environment?

### Other information