update CHANGELOG and README

[skip ci]

Author: doghappy

CHANGELOG.md

@@ -7,7 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [3.0.0] - 2021-9-13
 
-SocketIOClient v3.x supports http polling and websocket, socket.io server v2.x is no longer supported.
+SocketIOClient v3.0.0 supports http polling and websocket, socket.io server v2.x is no longer supported.
 
 ### Added
 

README.md

@@ -262,7 +262,7 @@ client.ClientWebSocketProvider = () => new ClientWebSocketManaged();
 
 # Breaking changes
 
-## Breaking changes in 3.x
+## Breaking changes in 3.0.0
 
 > While WebSocket is clearly the best way to establish a bidirectional communication, experience has shown that it is not always possible to establish a WebSocket connection, due to corporate proxies, personal firewall, antivirus software…