excon-hypermedia.gemspec in excon-hypermedia-0.5.2 vs excon-hypermedia.gemspec in excon-hypermedia-0.5.3

@@ -21,9 +21,10 @@
   spec.add_development_dependency 'rake', '~> 10.0'
   spec.add_development_dependency 'minitest', '~> 5.0'
   spec.add_development_dependency 'rubocop', '~> 0.40'
   spec.add_development_dependency 'pry', '~> 0.10'
   spec.add_development_dependency 'm', '~> 1.5'
+  spec.add_development_dependency 'open4', '~> 1.3'
 
   spec.add_dependency 'backport_dig' if RUBY_VERSION < '2.3'
   spec.add_dependency 'excon', '~> 0.49'
   spec.add_dependency 'excon-addressable', '~> 0.3'
 end