message: fix(components): allow Sidebar custom styles with a className prop
  Custom styles can then be passed on to the component using Emotion's css prop
diff: @@ -57,9 +57,11 @@ const openStyles = ({ theme, open }) =>
  const Drawer = styled('div')(baseStyles, openStyles);
  -const Sidebar = ({ children, open, closeButtonLabel, onClose }) => (
  +const Sidebar = ({ children, open, closeButtonLabel, onClose, className }) => (
  <Fragment>
  - <Drawer open={open}>{children}</Drawer>
  + <Drawer open={open} className={className}>
  + {children}
  + </Drawer>
  <Backdrop visible={open} onClick={onClose} />
  <CloseButton
  visible={open}
  @@ -85,7 +87,11 @@ Sidebar.propTypes = {
  /**
  * A function to handle the sidebar close
  */
  - onClose: PropTypes.func
  + onClose: PropTypes.func,
  + /**
  + * A className to allow custom styles with Emotion's css prop
  + */
  + className: PropTypes.string
  };
  Sidebar.defaultProps = {
  