BAU: Bump govuk-frontend from 5.14.0 to 6.1.0

Bumps [govuk-frontend](https://github.com/alphagov/govuk-frontend/tree/HEAD/packages/govuk-frontend) from 5.14.0 to 6.1.0.
- [Release notes](https://github.com/alphagov/govuk-frontend/releases)
- [Changelog](https://github.com/alphagov/govuk-frontend/blob/main/CHANGELOG.md)
- [Commits](https://github.com/alphagov/govuk-frontend/commits/v6.1.0/packages/govuk-frontend)

---
updated-dependencies:
- dependency-name: govuk-frontend
  dependency-version: 6.1.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Author: dependabot[bot]