Update README for third-party dependency metions

- Replaces the swift-sodium mention with TweetNacl
- Removes the Starscream mention

Author: danielrbrowne

README.md

@@ -1168,8 +1168,7 @@ PusherSwift is owned and maintained by [Pusher](https://pusher.com). It was orig
 It uses code from the following repositories:
 
 - [Reachability.swift](https://github.com/ashleymills/Reachability.swift)
-- [Starscream](https://github.com/daltoniam/Starscream) (removed in v9.0.0)
-- [Sodium](https://github.com/jedisct1/swift-sodium)
+- [TweetNacl](https://github.com/bitmark-inc/tweetnacl-swiftwrap)
 
 The individual licenses for these libraries are included in the corresponding Swift files.