Update system requirements in README

Author: albinekcom

README.md

@@ -54,7 +54,7 @@ discussed below.
 macOS, Ubuntu Linux LTS, and the latest Ubuntu Linux release are the current
 supported host development operating systems.
 
-For macOS, you need [Xcode 8.3 Beta 4](https://developer.apple.com/xcode/downloads/).
+For macOS, you need [Xcode 8.3](https://developer.apple.com/xcode/downloads/).
 
 For Ubuntu, you'll need the following development dependencies: