app_queue: add upgrade notes for 375216

Adds UPGRADE notes describing behavioral changes to rrmemory strategy caused by
375216

(issue AST-989)
Reported by: Thomas Arimont


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@375249 65c4cc65-6c06-0410-ace0-fbb531ad65f3

UPGRADE.txt

@@ -31,6 +31,9 @@ AMI:
 Queue:
  - Queue logging for PAUSEALL/UNPAUSEALL now only occurs if the interface this is
    performed on is a member of at least one queue.
+ - Queue strategy rrmemory now has a predictable order similar to strategy
+   rrordered. Members will be called in the order that they are added to the
+   queue.
 
 Dial:
  - Now recognizes 'W' to pause sending DTMF for one second in addition to