Bump @percy/storybook from 5.0.1 to 6.0.0

Bumps [@percy/storybook](https://github.com/percy/percy-storybook) from 5.0.1 to 6.0.0.
- [Release notes](https://github.com/percy/percy-storybook/releases)
- [Commits](percy/percy-storybook@v5.0.1...v6.0.0)

---
updated-dependencies:
- dependency-name: "@percy/storybook"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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