main: add TODO

src/main.rs

@@ -23,6 +23,8 @@ struct JobSender(Mutex<Sender<Job>>);
 
 #[post("/", data = "<payload>")]
 fn gitea_webhook(payload: Json<GiteaWebHook>, sender: State<JobSender>) -> Status {
+    // TODO: validate Gitea signature
+
     {
         let sender = sender.0.lock().unwrap();
         let repo = &payload.repository;