Fix dependencies

.rubocop.yml

@@ -2,6 +2,10 @@ AllCops:
   TargetRubyVersion: 2.6
   NewCops: enable
 
+Gemspec/DevelopmentDependencies:
+  Enabled: true
+  EnforcedStyle: gemspec
+
 Style/StringLiterals:
   Enabled: true
   EnforcedStyle: double_quotes

xml2json.gemspec

@@ -41,23 +41,23 @@ Gem::Specification.new do |spec|
 
   # Uncomment to register a new dependency of your gem
   # spec.add_dependency "example-gem", "~> 1.0"
-  spec.add_dependency "rake", "~> 13.0"
+  spec.add_development_dependency "rake", "~> 13.0"
 
-  spec.add_dependency "rake-compiler"
-  spec.add_dependency "rb_sys", "~> 0.9.63"
+  spec.add_development_dependency "rake-compiler"
+  spec.add_development_dependency "rb_sys", "~> 0.9.63"
 
-  spec.add_dependency "rspec", "~> 3.0"
+  spec.add_development_dependency "rspec", "~> 3.0"
 
-  spec.add_dependency "rubocop", "~> 1.21"
+  spec.add_development_dependency "rubocop", "~> 1.21"
 
-  spec.add_dependency "pry"
-  spec.add_dependency "pry-byebug"
-  spec.add_dependency "yard"
+  spec.add_development_dependency "pry"
+  spec.add_development_dependency "pry-byebug"
+  spec.add_development_dependency "yard"
   # # Cause I want to use rack adapter
-  spec.add_dependency "rack"
-  spec.add_dependency "rackup"
+  spec.add_development_dependency "rack"
+  spec.add_development_dependency "rackup"
   # # Cause I want to use rack adapter with puma server
-  spec.add_dependency "puma"
+  spec.add_development_dependency "puma"
 
   # For more information and examples about making a new gem, check out our
   # guide at: https://bundler.io/guides/creating_gem.html