fix: build issue with "React is not defined"

src/__test__/index.test.tsx

@@ -1,3 +1,4 @@
+import React from 'react'
 import { render, cleanup, fireEvent } from '@testing-library/react'
 
 import { Form, HandleForm } from '..'

src/__test__/setup.ts

@@ -1,3 +0,0 @@
-import React from 'react'
-
-global.React = React

src/index.tsx

@@ -1,4 +1,4 @@
-import { useRef } from 'react'
+import React, { useRef } from 'react'
 
 export interface FormDataObject {
   [key: string]: FormDataEntryValue