add macos as supported platform

Author: ryanlntn

RNSha256.podspec

@@ -11,7 +11,7 @@ Pod::Spec.new do |s|
   s.homepage     = package["homepage"]
 
   s.license      = package["license"]
-  s.platform     = :ios, "8.0"
+  s.platforms    = { :ios => "9.0", :osx => "10.14" }
 
   s.source       = { :git => "https://github.com/itinance/react-native-sha256.git", :tag => "#{s.version}" }
   s.source_files = "ios/**/*.{h,m,swift}"