message: fix(button-group): implement add/remove buttons
diff: import React from 'react';
  import { storiesOf } from '@storybook/react';
  -import { withKnobs, text, select } from '@storybook/addon-knobs';
  +import { withKnobs, text, select, number } from '@storybook/addon-knobs';
  import { ArrowRight20, ArrowDown20, Pdf20 } from '@carbon/icons-react';
  import readme from '../README.md';
  import { DDS_BUTTON_GROUP } from '../../../internal/FeatureFlags';
  @@ -31,27 +31,19 @@ if (DDS_BUTTON_GROUP) {
  PDF: 'Pdf20',
  };
  - const primaryIcon =
  - iconMap[
  - select('Primary button icon', iconOptions, iconOptions['Arrow Right'])
  - ];
  - const secondaryIcon =
  - iconMap[
  - select('Secondary button icon', iconOptions, iconOptions['PDF'])
  - ];
  + const buttonCount = number('Number of buttons', 2);
  + const buttons = [];
  - const buttons = [
  - {
  - href: 'https://www.ibm.com',
  - copy: text('Primary button copy', 'Primary action button'),
  - renderIcon: primaryIcon || null,
  - },
  - {
  - href: 'https://www.ibm.com',
  - copy: text('Secondary button copy', 'Secondary action button'),
  - renderIcon: secondaryIcon || null,
  - },
  - ];
  + for (let i = 0; i < buttonCount; i++) {
  + buttons.push({
  + link: text(`Link ${i + 1}`, `https://example.com`),
  + copy: text(`Button ${i + 1}`, `Button ${i + 1}`),
  + renderIcon:
  + iconMap[
  + select(`Icon ${i + 1}`, iconOptions, iconOptions['Arrow Right'])
  + ],
  + });
  + }
  return (
  <div
  