Fix Carthage installation guide (#3107)

README.md

@@ -92,7 +92,7 @@ pod 'Alamofire', '~> 5.0'
 [Carthage](https://github.com/Carthage/Carthage) is a decentralized dependency manager that builds your dependencies and provides you with binary frameworks. To integrate Alamofire into your Xcode project using Carthage, specify it in your `Cartfile`:
 
 ```ogdl
-github "Alamofire/Alamofire" "5.0"
+github "Alamofire/Alamofire" ~> 5.0
 ```
 
 ### Swift Package Manager