Bump slimmer from 17.0.0 to 18.0.0
Bump slimmer from 17.0.0 to 18.0.0

Bumps [slimmer](https://github.com/alphagov/slimmer) from 17.0.0 to 18.0.0.
- [Release notes](https://github.com/alphagov/slimmer/releases)
- [Changelog](https://github.com/alphagov/slimmer/blob/main/CHANGELOG.md)
- [Commits](https://github.com/alphagov/slimmer/compare/v17.0.0...v18.0.0)

---
updated-dependencies:
- dependency-name: slimmer
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
alphagov/collections,alphagov/collections,alphagov/collections,alphagov/collections