fix bundler version

Author: sirupsen

airrecord.gemspec

@@ -23,7 +23,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'faraday', ['>= 0.10', '< 2.0']
   spec.add_dependency "net-http-persistent", '>= 2.9'
 
-  spec.add_development_dependency "bundler", "~> 2.2"
+  spec.add_development_dependency "bundler", "~> 2"
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "minitest", "~> 5.0"
   spec.add_development_dependency "byebug"