Update package.json version to 4.0.0 [ci skip]

package.json

 {
   "name": "react-native-navigation",
-  "version": "3.7.0",
+  "version": "4.0.0",
   "description": "React Native Navigation - truly native navigation for iOS and Android",
   "license": "MIT",
   "nativePackage": true,
       }
     }
   }
-}
+}