Bump govuk_app_config from 9.14.6 to 9.15.0

Bumps [govuk_app_config](https://github.com/alphagov/govuk_app_config) from 9.14.6 to 9.15.0.
- [Changelog](https://github.com/alphagov/govuk_app_config/blob/main/CHANGELOG.md)
- [Commits](alphagov/govuk_app_config@v9.14.6...v9.15.0)

---
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

@@ -79,7 +79,7 @@ GEM
       rake (>= 13)
     googleapis-common-protos-types (1.16.0)
       google-protobuf (>= 3.18, < 5.a)
-    govuk_app_config (9.14.6)
+    govuk_app_config (9.15.0)
       logstasher (~> 2.1)
       opentelemetry-exporter-otlp (>= 0.25, < 0.30)
       opentelemetry-instrumentation-all (>= 0.39.1, < 0.69.0)
@@ -364,9 +364,8 @@ GEM
       rack (>= 3.0.0)
     rack-test (2.1.0)
       rack (>= 1.3)
-    rackup (2.1.0)
+    rackup (2.2.0)
       rack (>= 3)
-      webrick (~> 1.8)
     rails-dom-testing (2.2.0)
       activesupport (>= 5.0.0)
       minitest
@@ -476,7 +475,7 @@ GEM
       addressable (>= 2.8.0)
       crack (>= 0.3.2)
       hashdiff (>= 0.4.0, < 2.0.0)
-    webrick (1.8.2)
+    webrick (1.9.0)
     zeitwerk (2.7.1)
 
 PLATFORMS