fix typo in NEWS file

NEWS

@@ -71,8 +71,8 @@ release/005.000 (2016-11-21)
 
     Clients installing their own custom sources are advised to move all of that
     into separate classes, and to put those classes into a new phase of their
-    own.  This new phase should "require => Phase['aptitude']" and
-    "before => Phase['main']", to ensure proper execution sequencing.
+    own.  This new phase should "require => Stage['aptitude']" and
+    "before => Stage['main']", to ensure proper execution sequencing.
 
     [os/debian] Add two Hiera-configurable parameters to base::os::debian::apt: