Add other available platforms to podspec

Author: solidcell

RxSwiftUtilities.podspec

@@ -9,6 +9,9 @@ Helpful classes and extensions for RxSwift which don't belong in RxSwift core.
   s.license      = { :type => "MIT", :file => "LICENSE.md" }
   s.author       = { "Jesse Farless" => "[email protected]" }
   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.source       = { :git => "https://github.com/RxSwiftCommunity/RxSwiftUtilities.git", :tag => "#{s.version}" }
   s.source_files = 'Source/*.swift'
   s.dependency   "RxSwift", "~> 3.0"