Bump govuk_publishing_components from 12.4.0 to 12.6.0

Bumps [govuk_publishing_components](https://github.com/alphagov/govuk_publishing_components) from 12.4.0 to 12.6.0.
- [Release notes](https://github.com/alphagov/govuk_publishing_components/releases)
- [Changelog](https://github.com/alphagov/govuk_publishing_components/blob/master/CHANGELOG.md)
- [Commits](alphagov/govuk_publishing_components@v12.4.0...v12.6.0)

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

Gemfile

@@ -6,7 +6,7 @@ gem 'gds-api-adapters', '~> 54.1.2'
 gem 'govuk_app_config', '~> 1.10'
 gem 'govuk_elements_rails'
 gem 'govuk_frontend_toolkit', '~> 8.1.0'
-gem 'govuk_publishing_components', '~> 12.4.0'
+gem 'govuk_publishing_components', '~> 12.6.0'
 gem 'plek', '2.1.1'
 gem 'rails', '~> 5.2.1'
 gem 'rails-i18n', '~> 5.1.2'

Gemfile.lock

@@ -78,7 +78,7 @@ GEM
     coderay (1.1.2)
     commander (4.4.7)
       highline (~> 2.0.0)
-    concurrent-ruby (1.0.5)
+    concurrent-ruby (1.1.3)
     crack (0.4.3)
       safe_yaml (~> 1.0.0)
     crass (1.0.4)
@@ -128,7 +128,7 @@ GEM
     govuk_frontend_toolkit (8.1.0)
       railties (>= 3.1.0)
       sass (>= 3.2.0)
-    govuk_publishing_components (12.4.0)
+    govuk_publishing_components (12.6.0)
       govspeak (>= 5.0.3)
       govuk_app_config
       govuk_frontend_toolkit
@@ -371,7 +371,7 @@ DEPENDENCIES
   govuk_app_config (~> 1.10)
   govuk_elements_rails
   govuk_frontend_toolkit (~> 8.1.0)
-  govuk_publishing_components (~> 12.4.0)
+  govuk_publishing_components (~> 12.6.0)
   jasmine-rails
   listen (>= 3.0.5, < 3.2)
   phantomjs (~> 2.1.1)