RuboCop’s installation is pretty standard:
$ gem install rubocop
If you’d rather install RuboCop using
bundler, don’t require it in your
gem 'rubocop', require: false
RuboCop is stable between major versions, both in terms of API and cop configuration.
We aim the ease the maintenance of RuboCop extensions and the upgrades between RuboCop
releases. All big changes are reserved for major releases.
To prevent an unwanted RuboCop update you might want to use a conservative version lock
gem 'rubocop', '~> 1.39', require: false