Bump govuk_app_config from 1.16.3 to 1.18.1
Bump govuk_app_config from 1.16.3 to 1.18.1

Bumps [govuk_app_config](https://github.com/alphagov/govuk_app_config) from 1.16.3 to 1.18.1.
- [Release notes](https://github.com/alphagov/govuk_app_config/releases)
- [Changelog](https://github.com/alphagov/govuk_app_config/blob/master/CHANGELOG.md)
- [Commits](https://github.com/alphagov/govuk_app_config/compare/v1.16.3...v1.18.1)
alphagov/smart-answers,alphagov/smart-answers,alphagov/smart-answers,alphagov/smart-answers