Add rubocop-govuk

This is the only Ruby repository owned by the Publishing Platform team
that does not include rubocop.

Therefore adding it to make sure the code here remains consistent.

Author: brucebolt

.govuk_dependabot_merger.yml

@@ -4,3 +4,7 @@ auto_merge:
     allowed_semver_bumps:
       - patch
       - minor
+  - dependency: rubocop-govuk
+    allowed_semver_bumps:
+      - patch
+      - minor

.rubocop.yml

@@ -0,0 +1,17 @@
+inherit_gem:
+  rubocop-govuk:
+    - config/default.yml
+
+inherit_mode:
+  merge:
+    - Exclude
+
+# **************************************************************
+# TRY NOT TO ADD OVERRIDES IN THIS FILE
+#
+# This repo is configured to follow the RuboCop GOV.UK styleguide.
+# Any rules you override here will cause this repo to diverge from
+# the way we write code in all other GOV.UK repos.
+#
+# See https://github.com/alphagov/rubocop-govuk/blob/main/CONTRIBUTING.md
+# **************************************************************

Gemfile

@@ -2,3 +2,7 @@ source 'https://rubygems.org'
 
 gem 'govuk_tech_docs'
 gem 'middleman-gh-pages', '~> 0.4.1'
+
+group :development, :test do
+  gem "rubocop-govuk"
+end

Gemfile.lock

@@ -8,6 +8,7 @@ GEM
       tzinfo (~> 2.0)
     addressable (2.8.6)
       public_suffix (>= 2.0.2, < 6.0)
+    ast (2.4.2)
     autoprefixer-rails (10.4.16.0)
       execjs (~> 2)
     backports (3.24.1)
@@ -65,8 +66,10 @@ GEM
     http_parser.rb (0.8.0)
     i18n (1.6.0)
       concurrent-ruby (~> 1.0)
+    json (2.7.1)
     kramdown (2.4.0)
       rexml
+    language_server-protocol (3.17.0.3)
     listen (3.8.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
@@ -140,19 +143,59 @@ GEM
       tilt (>= 1.4.1, < 3)
     padrino-support (0.15.3)
     parallel (1.24.0)
+    parser (3.3.0.5)
+      ast (~> 2.4.1)
+      racc
     parslet (2.0.0)
     public_suffix (5.0.4)
     racc (1.7.3)
     rack (2.2.8.1)
     rack-livereload (0.3.17)
       rack
+    rainbow (3.1.1)
     rake (13.0.6)
     rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
     redcarpet (3.5.1)
+    regexp_parser (2.9.0)
     rexml (3.2.6)
     rouge (3.30.0)
+    rubocop (1.60.2)
+      json (~> 2.3)
+      language_server-protocol (>= 3.17.0)
+      parallel (~> 1.10)
+      parser (>= 3.3.0.2)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 1.8, < 3.0)
+      rexml (>= 3.2.5, < 4.0)
+      rubocop-ast (>= 1.30.0, < 2.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 2.4.0, < 3.0)
+    rubocop-ast (1.30.0)
+      parser (>= 3.2.1.0)
+    rubocop-capybara (2.20.0)
+      rubocop (~> 1.41)
+    rubocop-factory_bot (2.25.1)
+      rubocop (~> 1.41)
+    rubocop-govuk (4.14.0)
+      rubocop (= 1.60.2)
+      rubocop-ast (= 1.30.0)
+      rubocop-rails (= 2.23.1)
+      rubocop-rake (= 0.6.0)
+      rubocop-rspec (= 2.26.1)
+    rubocop-rails (2.23.1)
+      activesupport (>= 4.2.0)
+      rack (>= 1.1)
+      rubocop (>= 1.33.0, < 2.0)
+      rubocop-ast (>= 1.30.0, < 2.0)
+    rubocop-rake (0.6.0)
+      rubocop (~> 1.0)
+    rubocop-rspec (2.26.1)
+      rubocop (~> 1.40)
+      rubocop-capybara (~> 2.17)
+      rubocop-factory_bot (~> 2.22)
+    ruby-progressbar (1.13.0)
     sass (3.4.25)
     sassc (2.4.0)
       ffi (~> 1.9)
@@ -169,6 +212,7 @@ GEM
       concurrent-ruby (~> 1.0)
     uglifier (3.2.0)
       execjs (>= 0.3.0, < 3)
+    unicode-display_width (2.5.0)
     webrick (1.8.1)
 
 PLATFORMS
@@ -177,6 +221,7 @@ PLATFORMS
 DEPENDENCIES
   govuk_tech_docs
   middleman-gh-pages (~> 0.4.1)
+  rubocop-govuk
 
 BUNDLED WITH
    2.3.26