remove bundler as dev dependency

Author: manuca

skunk.gemspec

@@ -41,7 +41,6 @@ Gem::Specification.new do |spec|
   spec.add_dependency "rubycritic", ">= 4.4", "< 5.0"
   spec.add_dependency "terminal-table", "~> 1.8.0"
 
-  spec.add_development_dependency "bundler", "~> 2.0"
   spec.add_development_dependency "byebug", "~> 11"
   spec.add_development_dependency "codecov", "~> 0.1.16"
   spec.add_development_dependency "minitest", "~> 5.8.4"