Update websocket.md

Author: luc-github

Memo/websocket.md

@@ -36,6 +36,9 @@ Format: `<label>:<message>`
     -   `NOTIFICATION:<message>`
         Forward the message sent by [ESP600] to webUI toast system
 
+    -   `SENSOR: <value>[<unit>] <value2>[<unit2>] ...
+        The sensor connected to ESP like DHT22
+
 -   from WebUI to ESP
     -   `PING:<current cookiesessionID / none >` if any, or "none" if none