Update CHANGES and UPGRADE.txt for 18.6.0

CHANGES

@@ -12,6 +12,32 @@
 ===
 ==============================================================================
 
+------------------------------------------------------------------------------
+--- Functionality changes from Asterisk 18.5.0 to Asterisk 18.6.0 ------------
+------------------------------------------------------------------------------
+
+Handle non-standard Meter metric type safely
+------------------
+ * A meter_support flag has been introduced that defaults to true to maintain current behaviour.
+   If disabled, a counter metric type will be used instead wherever a meter metric type was used,
+   the counter will have a "_meter" suffix appended to the metric name.
+
+app_dtmfstore
+------------------
+ * New application which collects digits
+   dialed and stores them into
+   a specified variable.
+
+app_queue.c
+------------------
+ * Allow multiple files to be streamed for agent announcement.
+
+chan_pjsip
+------------------
+ * Add function PJSIP_HEADERS() to get list of headers by pattern in the same way as SIP_HEADERS() do.
+
+   Add ability to read header by pattern using PJSIP_HEADER().
+
 ------------------------------------------------------------------------------
 --- Functionality changes from Asterisk 18.5.0 to Asterisk 18.5.1 ------------
 ------------------------------------------------------------------------------

doc/CHANGES-staging/app_dtmfstore.txt

-Subject: app_dtmfstore
-
-New application which collects digits
-dialed and stores them into
-a specified variable.
-

doc/CHANGES-staging/app_queue.txt

-Subject: app_queue.c
-
-Allow multiple files to be streamed for agent announcement.
-

doc/CHANGES-staging/pjsip_read_headers.txt

-Subject: chan_pjsip
-
-Add function PJSIP_HEADERS() to get list of headers by pattern in the same way as SIP_HEADERS() do.
-
-Add ability to read header by pattern using PJSIP_HEADER().

doc/CHANGES-staging/res_statsd.txt

-Subject: Handle non-standard Meter metric type safely
-
-A meter_support flag has been introduced that defaults to true to maintain current behaviour.
-If disabled, a counter metric type will be used instead wherever a meter metric type was used,
-the counter will have a "_meter" suffix appended to the metric name.
\ No newline at end of file