Bump y18n from 4.0.0 to 4.0.3 in /storybook

Bumps [y18n](https://github.com/yargs/y18n) from 4.0.0 to 4.0.3.
- [Release notes](https://github.com/yargs/y18n/releases)
- [Changelog](https://github.com/yargs/y18n/blob/y18n-v4.0.3/CHANGELOG.md)
- [Commits](yargs/y18n@v4.0.0...y18n-v4.0.3)

---
updated-dependencies:
- dependency-name: y18n
  dependency-type: indirect
...

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

Author: dependabot[bot]