Bump govuk_app_config from 1.2.0 to 1.2.1
Bump govuk_app_config from 1.2.0 to 1.2.1

Bumps [govuk_app_config](https://github.com/alphagov/govuk_app_config) from 1.2.0 to 1.2.1.
- [Changelog](https://github.com/alphagov/govuk_app_config/blob/master/CHANGELOG.md)
- [Commits](https://github.com/alphagov/govuk_app_config/compare/v1.2.0...v1.2.1)
alphagov/collections-publisher,alphagov/collections-publisher,alphagov/collections-publisher