Merge pull request #239 from koic/reduce_release_package_size

Reduce release package size

mcp.gemspec

@@ -23,9 +23,7 @@ Gem::Specification.new do |spec|
   spec.metadata["bug_tracker_uri"] = "#{spec.homepage}/issues"
   spec.metadata["documentation_uri"] = "https://rubydoc.info/gems/mcp"
 
-  spec.files = Dir.chdir(File.expand_path("..", __FILE__)) do
-    %x(git ls-files -z).split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
-  end
+  spec.files = Dir["LICENSE", "README.md", "lib/**/*"]
 
   spec.bindir        = "exe"
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }