Bump govuk_app_config from 3.1.1 to 3.2.0

Bumps [govuk_app_config](https://github.com/alphagov/govuk_app_config) from 3.1.1 to 3.2.0.
- [Release notes](https://github.com/alphagov/govuk_app_config/releases)
- [Changelog](https://github.com/alphagov/govuk_app_config/blob/v3.2.0/CHANGELOG.md)
- [Commits](alphagov/govuk_app_config@v3.1.1...v3.2.0)

---
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

@@ -118,7 +118,7 @@ GEM
       activesupport (>= 4.2.0)
     govuk-content-schema-test-helpers (1.6.1)
       json-schema (~> 2.8.0)
-    govuk_app_config (3.1.1)
+    govuk_app_config (3.2.0)
       logstasher (>= 1.2.2, < 2.2.0)
       sentry-raven (~> 3.1.1)
       statsd-ruby (~> 1.5.0)