Updates CHANGES to reflect the new externtcpport and externtlsport sip options

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@222399 65c4cc65-6c06-0410-ace0-fbb531ad65f3

CHANGES

@@ -44,6 +44,8 @@ SIP Changes
  * Slave SIP channels now set HASH(SIP_CAUSE,<slave-channel-name>) on each
    response.  This permits the master channel to know how each channel dialled
    in a multi-channel setup resolved in an individual way.
+ * Added 'externtcpport' and 'externtlsport' options to allow custom port
+   configuration for the externip and externhost options when tcp or tls is used.
 
 IAX2 Changes
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