Bump govuk_app_config from 4.7.1 to 4.8.0

Bumps [govuk_app_config](https://github.com/alphagov/govuk_app_config) from 4.7.1 to 4.8.0.
- [Release notes](https://github.com/alphagov/govuk_app_config/releases)
- [Changelog](https://github.com/alphagov/govuk_app_config/blob/main/CHANGELOG.md)
- [Commits](alphagov/govuk_app_config@v4.7.1...v4.8.0)

---
updated-dependencies:
- dependency-name: govuk_app_config
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -123,7 +123,7 @@ GEM
     globalid (1.0.0)
       activesupport (>= 5.0)
     govuk_ab_testing (2.4.2)
-    govuk_app_config (4.7.1)
+    govuk_app_config (4.8.0)
       logstasher (~> 2.1)
       prometheus_exporter (~> 2.0)
       puma (~> 5.6)