message: Configurable heights on HorizontalRule
diff: import styled from 'styled-components';
  -import { themeGet, space } from 'styled-system';
  +import { themeGet, space, height } from 'styled-system';
  import { preset } from 'react/styles/functions';
  export default styled.hr`
  ${preset(space, { my: 6 })}
  - height: 1px;
  + ${preset(height, { height: '1px' })}
  border: none;
  background-color: ${(props) => {
  if (props.invisible) return 'transparent';
  