[docs] update README.md (#3309)

Author: Yorkshireman

Readme.md

@@ -11,7 +11,7 @@
 
 ## Features
 
-Socket.IO enables real-time bidirectional event-based communication. It consists in:
+Socket.IO enables real-time bidirectional event-based communication. It consists of:
 
 - a Node.js server (this repository)
 - a [Javascript client library](https://github.com/socketio/socket.io-client) for the browser (or a Node.js client)