documentation update: notify is deprecated

README.md

@@ -145,6 +145,7 @@ If `$reason` itself is a promise, the promise will be rejected with the outcome
 of this promise regardless whether it fulfills or rejects.
 
 #### Deferred::notify()
+**DEPRECATED** Progress notification is deprecated. Will be removed in upcoming versions.  
 
 ```php
 $deferred->notify(mixed $update = null);

src/Deferred.php

@@ -42,6 +42,9 @@ public function reject($reason = null)
         call_user_func($this->rejectCallback, $reason);
     }
 
+    /**
+     * @deprecated 2.2.0
+     */
     public function notify($update = null)
     {
         $this->promise();