Update requirements docs (#468)

README.md

@@ -4,6 +4,8 @@
 [![Version](https://img.shields.io/cocoapods/v/Lock.svg?style=flat-square)](http://cocoadocs.org/docsets/Lock)
 [![License](https://img.shields.io/cocoapods/l/Lock.svg?style=flat-square)](http://cocoadocs.org/docsets/Lock)
 [![Platform](https://img.shields.io/cocoapods/p/Lock.svg?style=flat-square)](http://cocoadocs.org/docsets/Lock)
+[![Carthage compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg?style=flat-square)](https://github.com/Carthage/Carthage)
+![Swift 3.1](https://img.shields.io/badge/Swift-3.1-orange.svg?style=flat-square)
 
 [Auth0](https://auth0.com) is an authentication broker that supports social identity providers as well as enterprise identity providers such as Active Directory, LDAP, Google Apps and Salesforce.
 
@@ -19,8 +21,8 @@ Need help migrating from v1? Please check our [Migration Guide](MIGRATION.md)
 ## Requirements
 
 - iOS 9 or later
-- Xcode 8
-- Swift 3.0
+- Xcode 8.3 / 9.0
+- Swift 3.1+
 
 ## Install