make Podspec pass validation

Author: DivineDominion

ReSwiftRouter.podspec

@@ -10,13 +10,13 @@ Pod::Spec.new do |s|
   s.homepage         = "https://github.com/ReSwift/ReSwift-Router"
   s.license          = { :type => "MIT", :file => "LICENSE.md" }
   s.author           = { "Benjamin Encz" => "[email protected]" }
-  s.social_media_url = "http://twitter.com/benjaminencz"
   s.source           = { :git => "https://github.com/ReSwift/ReSwift-Router.git", :tag => s.version.to_s }
   s.ios.deployment_target     = '8.0'
   s.osx.deployment_target     = '10.10'
   s.tvos.deployment_target    = '9.0'
   s.watchos.deployment_target = '2.0'
   s.requires_arc = true
   s.source_files     = 'ReSwiftRouter/**/*.swift'
+  s.swift_versions   = [ "5.0", "4.2" ]
   s.dependency 'ReSwift', '~> 5.0.0'
 end