update podspec

ReactNativeNavigation.podspec

 Pod::Spec.new do |s|
   s.name         = "ReactNativeNavigation"
   s.version      = package['version']
-  s.summary      = "A Native Navigation Solution for React Native"
+  s.summary      = package['description']
 
-  s.authors      = "Wix"
-  s.homepage     = "https://github.com/wix/react-native-navigation.git#readme"
+  s.authors      = "Wix.com"
+  s.homepage     = package['homepage']
   s.license      = package['license']
   s.platform     = :ios, "9.0"