Speed up rubocop CI job

.gitlab-ci.yml

@@ -268,8 +268,10 @@ rubocop:
   stage: check
   <<: *dedicated-runner
   image: ruby:2.3.3
+  before_script:
+    - bundle install -j $(nproc) --binstubs --path gems --without default test
   script:
-    - bundle exec rake rubocop
+    - bundle exec rubocop --parallel
   except:
     - branches@gitlab/omnibus-gitlab
     - tags@gitlab/omnibus-gitlab

CHANGELOG.md

@@ -5,13 +5,14 @@ omnibus-gitlab repository.
 
 10.7.0
 - Geo: Increase default WAL standby settings from 30s to 60s
+- Internal: Speed up rubocop job (Takuya Noguchi)
 
 10.6.0
 
 - Warn users of stale sprockets manifest file after install 8d4cd46c (David Haltinner)
 - Geo: Don't attempt to refresh FDW tables if FDW is not enabled
 - Deprecate `/etc/gitlab/skip-auto-migrations` for `/etc/gitlab/skip-auto-reconfigure`
-- Update python to 3.4.8
+- Update python to 3.4.8 (Takuya Noguchi)
 - Update jemalloc to 5.0.1
 - Update chef to 13.6.4
 - Unsets `RUBYLIB` in `gitlab-rails`, `gitlab-rake`, and `gitlab-ctl` to avoid

Gemfile

@@ -22,10 +22,13 @@ gem 'json'
 gem 'rspec'
 gem 'rake'
 gem 'knapsack'
-gem 'rubocop'
 gem 'docker-api'
 gem 'aws-sdk'
-gem 'rubocop-rspec'
+
+group :rubocop do
+  gem 'rubocop'
+  gem 'rubocop-rspec'
+end
 
 group :test do
   gem 'byebug'

Rakefile

@@ -3,6 +3,3 @@
 require 'knapsack'
 Rake.add_rakelib 'lib/gitlab/tasks'
 Knapsack.load_tasks
-
-require 'rubocop/rake_task'
-RuboCop::RakeTask.new(:rubocop)