Update contributors file (celery#4190)

Nicolas Mota · Omer Katz · commit 2394e738a7d0 · 2017-08-10T23:52:31.000+03:00
diff --git a/CONTRIBUTORS.txt b/CONTRIBUTORS.txt
@@ -242,3 +242,4 @@ Anthony Lukach, 2017/05/23
 Samuel Dion-Girardeau, 2017/05/29
 Aydin Sen, 2017/06/14
 Preston Moore, 2017/06/18
+Nicolas Mota, 2017/08/10
