[ruby/pp] Removed needless files from Gem::Specification#files

https://github.com/ruby/pp/commit/272d4befeb

lib/pp.gemspec

@@ -14,9 +14,11 @@ Gem::Specification.new do |spec|
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage
 
-  spec.files         = Dir.chdir(File.expand_path('..', __FILE__)) do
-    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
-  end
+  spec.files         = %w[
+    LICENSE.txt
+    lib/pp.rb
+    pp.gemspec
+  ]
   spec.bindir        = "exe"
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]