Adds UPGRADE.txt notes to r357266 indicating changes to transport option

(issue ASTERISK-19352)
Reported by: jamicque


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@357356 65c4cc65-6c06-0410-ace0-fbb531ad65f3

UPGRADE.txt

@@ -172,6 +172,9 @@ From 1.6.2 to 1.8:
   are using the early media DTMF overlap dialing method you now need to set
   allowoverlap=dtmf.
 
+* If no transport is specified in sip.conf, transport will default to UDP.
+  Also, if multiple transport= lines are used, only the last will be used.
+
 From 1.6.1 to 1.6.2:
 
 * SIP no longer sends the 183 progress message for early media by