Pin RuboCop to avoid failures due to renamed cops

In RuboCop 1.0 this will stop happening, and we'll be able to relax it
to:

    gem 'rubocop', '~> 1.0'

Author: pirj

Gemfile

@@ -67,7 +67,7 @@ end
 
 gem "rubyzip", '~> 1.2'
 
-gem 'rubocop', "~> 0.74"
+gem 'rubocop', '~> 0.74.0'
 
 custom_gemfile = File.expand_path("../Gemfile-custom", __FILE__)
 eval_gemfile custom_gemfile if File.exist?(custom_gemfile)