style: fix gem ordering in Gemfile

Author: yhk1038

Gemfile

@@ -5,11 +5,11 @@ source "https://rubygems.org"
 gemspec
 
 group :development, :test do
+  gem "coveralls_reborn", "~> 0.28.0", require: false
   gem "rake", "~> 13.0"
   gem "rspec", "~> 3.0"
   gem "rspec_junit_formatter", "~> 0.6.0"
   gem "rubocop", require: false
   gem "simplecov", "~> 0.22.0", require: false
   gem "simplecov-lcov", "~> 0.8.0", require: false
-  gem "coveralls_reborn", "~> 0.28.0", require: false
 end