message: fix BorderBox lint issues
diff: import React from 'react'
  -import theme, {colors} from '../theme'
  +import {colors} from '../theme'
  import BorderBox from '../BorderBox'
  import Box from '../Box'
  -import {px, render, renderStyles} from '../utils/testing'
  +import {render} from '../utils/testing'
  describe('BorderBox', () => {
  it('is a system component', () => {
  