Supplying additional rules via useController to a form that already has a resolver

[giovannipiller]

I think it could be interesting to be able to:

1. provide a resolver to useForm, with the general validation rules for the form (already possible)
2. integrate them by supplying rules to a child component that uses useController

I find useController to be very useful when composing a form out of multiple components, due to its capability to keep validation rules close to the component that actually deals with that data.
Mixing and matching both approaches could be useful.

From my tests, this is currently not possible.
As an example, in the following scenario the rules provided to useController in the component <Field> are completely ignored.
Submitting the form will not execute the validation rules for “lastName”.
https://codesandbox.io/s/react-hook-form-resolver-forked-ol5xb

  const { field, fieldState } = useController({
    name: "lastName",
    rules: {
      required: "field required"
    }
  });

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I'm still kinda new to react-hook-form, hopefully I'm not proposing anything too crazy.