Bump storybook from 7.0.27 to 7.6.21 in /docs (#2949)

Bumps [storybook](https://github.com/storybookjs/storybook/tree/HEAD/code/core) from 7.0.27 to 7.6.21.
- [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/v7.6.21/code/core)

---
updated-dependencies:
- dependency-name: storybook
  dependency-version: 7.6.21
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]