Corrected Typo

Sample code for creating a new client for Windows 7 was using SocketIOClient(...) as the class however I believe it should be just SocketIO(...)

Author: griffinsorrentino

CHANGELOG.md

@@ -75,7 +75,7 @@ SocketIOClient v3.0.0 supports http polling and websocket, socket.io server v2.x
 SocketIOCLient.Windows7 becomes a plug-in, the following code shows how to support Windows7 / Windows 2008 R2
 
 ```cs
-var client = new SocketIOClient(...);
+var client = new SocketIO(...);
 client.Socket = new ClientWebSocketManaged();
 ```
 
@@ -249,4 +249,4 @@ No longer maintain `SocketIOClient.NetFx`, it is replaced by `SocketIOClient`. F
 
 ### Fixed
 
-- Fixed "Collection was modified" exception
+- Fixed "Collection was modified" exception