Use bundler 2.X

Author: jonleighton

spring-watcher-listen.gemspec

@@ -14,7 +14,7 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ["lib"]
 
-  spec.add_development_dependency "bundler", "~> 1.6"
+  spec.add_development_dependency "bundler", "~> 2.0"
   spec.add_development_dependency "rake"
   spec.add_development_dependency "activesupport"