Add version restriction for uri gem

The "uri" gem was updated last week and the new version has an incompatibility with the "cookiejar" library.

See ruby/uri#131

Author: jordan-brough

em-http-request.gemspec

@@ -17,6 +17,7 @@ Gem::Specification.new do |s|
 
   s.add_dependency 'addressable', '>= 2.3.4'
   s.add_dependency 'cookiejar', '!= 0.3.1'
+  s.add_dependency 'uri', '~> 0.13' # for compatibility with cookiejar, which is an archived project
   s.add_dependency 'em-socksify', '>= 0.3'
   s.add_dependency 'eventmachine', '>= 1.0.3'
   s.add_dependency 'http_parser.rb', '>= 0.6.0'