build(deps-dev): bump @storybook/test-runner from 0.19.1 to 0.20.1 (#660

)

Bumps [@storybook/test-runner](https://github.com/storybookjs/test-runner) from 0.19.1 to 0.20.1.
- [Release notes](https://github.com/storybookjs/test-runner/releases)
- [Changelog](https://github.com/storybookjs/test-runner/blob/v0.20.1/CHANGELOG.md)
- [Commits](storybookjs/test-runner@v0.19.1...v0.20.1)

---
updated-dependencies:
- dependency-name: "@storybook/test-runner"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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