Describe the bug

This is a great sample repo!

But it seems that #20 and #21 introduced syntax from react-hook-form v7, which breaks the app -- #21 breaks validation of the first name field, and #20 prevents the app from even starting.

To Reproduce
Steps to reproduce the behavior for #20 (startup issue):

1. Just try to yarn start, and it should fail.

Steps to reproduce the behavior for #20 (validation issue):

1. Go to first step
2. Focus and then blur the first name field
3. Focus and then blur the last name field

Expected behavior
Both fields (since blank, but required) should display validation messages.

Observed behavior
First name field doesn't show validation error, but last name field does.