Add rb_sys dependency

Author: bangseongbeom

urlpattern.gemspec

@@ -33,6 +33,7 @@ Gem::Specification.new do |spec|
 
   # Uncomment to register a new dependency of your gem
   # spec.add_dependency "example-gem", "~> 1.0"
+  spec.add_dependency "rb_sys", "~> 0.9.91"
 
   # For more information and examples about making a new gem, check out our
   # guide at: https://bundler.io/guides/creating_gem.html