chore(deps-dev): bump @storybook/react from 6.1.15 to 6.1.21

Bumps [@storybook/react](https://github.com/storybookjs/storybook/tree/HEAD/app/react) from 6.1.15 to 6.1.21.
- [Release notes](https://github.com/storybookjs/storybook/releases)
- [Changelog](https://github.com/storybookjs/storybook/blob/next/CHANGELOG.md)
- [Commits](https://github.com/storybookjs/storybook/commits/v6.1.21/app/react)

Signed-off-by: dependabot[bot] <[email protected]>