daemon: update monitor: implements ping/pong (required server changes)

kordophone/src/model/update.rs

@@ -12,6 +12,9 @@ pub struct UpdateItem {
 
     #[serde(rename = "message")]
     pub message: Option<Message>,
+
+    #[serde(default)]
+    pub pong: bool,
 }
 
 impl Default for UpdateItem {
@@ -20,6 +23,7 @@ impl Default for UpdateItem {
             seq: 0,
             conversation: None,
             message: None,
+            pong: false,
         }
     }
 }