Update README to point pod installation instructions to v5.0.1

Author: marcuswestin

README.md

@@ -18,7 +18,7 @@ Installation (iOS & OSX)
 Add this to your [podfile](https://guides.cocoapods.org/using/getting-started.html) and run `pod install` to install:
 
 ```ruby
-`pod 'WebViewJavascriptBridge', '~> 4.1.4'`
+`pod 'WebViewJavascriptBridge', '~> 5.0'`
 ```
 
 ### Manual installation