Add rubocop extensions: packaging, performance, rake

Author: teeparham

.rubocop.yml

@@ -1,16 +1,22 @@
 inherit_from: .rubocop_todo.yml
 
+require:
+  - rubocop-packaging
+  - rubocop-performance
+  - rubocop-rake
+
 AllCops:
   NewCops: enable
+  SuggestExtensions: false
   TargetRubyVersion: 3.0
 
 Layout/EmptyLineAfterGuardClause:
   Enabled: false
 
 Layout/HashAlignment:
   Exclude:
-    - 'lib/gemdiff/repo_finder.rb'
-    - 'lib/gemdiff/colorize.rb'
+    - "lib/gemdiff/repo_finder.rb"
+    - "lib/gemdiff/colorize.rb"
 
 Layout/LineLength:
   Max: 120
@@ -65,6 +71,6 @@ Style/ZeroLengthPredicate:
 
 Style/FrozenStringLiteralComment:
   Exclude:
-    - 'Gemfile'
-    - 'Rakefile'
-    - '*.gemspec'
+    - "Gemfile"
+    - "Rakefile"
+    - "*.gemspec"

Gemfile

@@ -4,7 +4,14 @@ source "https://rubygems.org"
 
 gem "minitest", "~> 5.21"
 gem "mocha", "~> 2.0"
-gem "pry-byebug" unless ENV["CI"]
 gem "rake", "~> 13.0"
 
+unless ENV["CI"]
+  gem "pry-byebug"
+  gem "rubocop", "~> 1.66"
+  gem "rubocop-packaging", "~> 0.5"
+  gem "rubocop-performance", "~> 1.22"
+  gem "rubocop-rake", "~> 0.6"
+end
+
 gemspec