Replace govuk-lint with rubocop-govuk and scss_lint-govuk

The GOV.UK Lint gem is deprecated in favour of using Rubocop and
scss_lint directly with a set of shared configs.

.rubocop.yml

@@ -1,3 +1,7 @@
+inherit_gem:
+  rubocop-govuk:
+    - "config/default.yml"
+
 Metrics/BlockLength:
   Exclude:
-    - 'test/**/*_test.rb'
+    - "test/**/*_test.rb"

.scss-lint.yml

@@ -0,0 +1 @@
+plugin_gems: ['scss_lint-govuk']

Gemfile

@@ -21,9 +21,10 @@ gem "slimmer", "~> 13.2"
 gem "uglifier", ">= 1.3.0"
 
 group :development, :test do
-  gem "govuk-lint"
   gem "govuk_schemas", "~> 4.0"
   gem "jasmine-rails"
+  gem "rubocop-govuk", "~> 1"
+  gem "scss_lint-govuk", "~> 0.2"
 end
 
 group :development do

Gemfile.lock

@@ -100,11 +100,6 @@ GEM
       rest-client (~> 2.0)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
-    govuk-lint (4.3.0)
-      rubocop (~> 0.76)
-      rubocop-rails (~> 2)
-      rubocop-rspec (~> 1.28)
-      scss_lint
     govuk_ab_testing (2.4.1)
     govuk_app_config (2.0.1)
       logstasher (>= 1.2.2, < 1.4.0)
@@ -264,10 +259,14 @@ GEM
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 1.7)
+    rubocop-govuk (1.0.0)
+      rubocop (~> 0.76)
+      rubocop-rails (~> 2)
+      rubocop-rspec (~> 1.28)
     rubocop-rails (2.3.2)
       rack (>= 1.1)
       rubocop (>= 0.72.0)
-    rubocop-rspec (1.36.0)
+    rubocop-rspec (1.37.0)
       rubocop (>= 0.68.1)
     ruby-progressbar (1.10.1)
     rubyzip (2.0.0)
@@ -293,6 +292,8 @@ GEM
       tilt
     scss_lint (0.59.0)
       sass (~> 3.5, >= 3.5.5)
+    scss_lint-govuk (0.2.0)
+      scss_lint
     selenium-webdriver (3.142.6)
       childprocess (>= 0.5, < 4.0)
       rubyzip (>= 1.2.2)
@@ -364,7 +365,6 @@ DEPENDENCIES
   dalli
   faker
   gds-api-adapters (~> 61.0)
-  govuk-lint
   govuk_ab_testing (~> 2.4)
   govuk_app_config (~> 2.0)
   govuk_frontend_toolkit (~> 8.2.0)
@@ -382,7 +382,9 @@ DEPENDENCIES
   rails-controller-testing (~> 1.0)
   rails-i18n (>= 4.0.4)
   rails_translation_manager (~> 0.1.0)
+  rubocop-govuk (~> 1)
   sass-rails (~> 5.0)
+  scss_lint-govuk (~> 0.2)
   slimmer (~> 13.2)
   uglifier (>= 1.3.0)
   webmock (~> 3.7.6)

Rakefile

@@ -4,3 +4,19 @@
 require File.expand_path('../config/application', __FILE__)
 
 Rails.application.load_tasks
+
+unless Rails.env.production?
+  require "rubocop/rake_task"
+  require "scss_lint/rake_task"
+
+  RuboCop::RakeTask.new(:rubocop) do |t|
+    t.patterns = %w(app config test Gemfile)
+  end
+
+  SCSSLint::RakeTask.new do |t|
+    t.files = Dir.glob(["app/assets/stylesheets"])
+  end
+
+  task default: %i[spec rubocop scss_lint]
+  task lint: %i[rubocop scss_lint]
+end