Drop git ls-files in gemspec

.rubocop.yml

@@ -1,4 +1,6 @@
-require: rubocop-rails
+require:
+  - rubocop-packaging
+  - rubocop-rails
 AllCops:
   NewCops: disable
   TargetRubyVersion: 2.4

Gemfile

@@ -7,6 +7,7 @@ gem 'pry-byebug'
 gem 'rake', '13.0.1'
 gem 'rspec', '~> 3.9'
 gem 'rubocop', require: false
+gem 'rubocop-packaging', require: false
 gem 'rubocop-rails', require: false
 gem 'warnings_logger'
 gem 'zeus', require: false

Gemfile.lock

@@ -51,6 +51,8 @@ GEM
       unicode-display_width (>= 1.4.0, < 2.0)
     rubocop-ast (0.3.0)
       parser (>= 2.7.1.4)
+    rubocop-packaging (0.4.0)
+      rubocop (~> 0.89)
     rubocop-rails (2.0.1)
       rack (>= 1.1)
       rubocop (>= 0.70.0)
@@ -76,6 +78,7 @@ DEPENDENCIES
   rouge
   rspec (~> 3.9)
   rubocop
+  rubocop-packaging
   rubocop-rails
   warnings_logger
   yard

shoulda-matchers.gemspec

@@ -27,10 +27,7 @@ Gem::Specification.new do |s|
     'source_code_uri' => 'https://github.com/thoughtbot/shoulda-matchers',
   }
 
-  s.files = Dir.chdir(File.expand_path(__dir__)) do
-    `git ls-files -z -- {docs,lib,README.md,MIT-LICENSE,shoulda-matchers.gemspec}`.
-      split("\x0")
-  end
+  s.files = Dir['{docs,lib}/**/*', 'README.md', 'MIT-LICENSE', 'shoulda-matchers.gemspec']
   s.require_paths = ['lib']
 
   s.required_ruby_version = '>= 2.4.0'

tasks/documentation.rb

@@ -1,4 +1,4 @@
-require_relative '../lib/shoulda/matchers/version'
+require 'shoulda/matchers/version'
 require 'erb'
 
 module Shoulda