Properly close web socket channel on .connectionClose event

Web socket was never actually closed since we only send data and Opcode back to the channel.
This closes the actual channel and stops the connection.

Author: zlmr

templates/swift/Sources/WebSockets/WebSocketClient.swift.twig

@@ -408,5 +408,9 @@ public class WebSocketClient {
         } else {
             channel.write(frame, promise: nil)
         }
+        
+        if opcode == .connectionClose {
+            channel.close(mode: .all, promise: nil)
+        }
     }
 }