Update CHANGES.md

Author: Doug Black

CHANGES.md

@@ -6,9 +6,15 @@ Here you can see the full list of changes between each twilio-python release.
 [2017-04-03] Version 6.1.0-alpha-1
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-- Add chat v2.
-- Add new Conference parameters.
-- Add `ValidityPeriod` parameter to Messages.
+- Add v2 of chat.twilio.com.
+- Add `recording_channels` parameter to Participant create and update.
+- Add `recording_status_callback` parameter to Participant create and update.
+- Add `recording_status_callback_method` parameter to Participant create and update.
+- Add `sip_auth_username` parameter to Participant create and update.
+- Add `region` parameter to Participant create and update.
+- Add `conference_recording_status_callback` parameter to Participant create and update.
+- Add `conference_recording_status_callback_method` parameter to Participant create and update.
+- Add `validity_period` parameter to Messages.
 
 [2017-04-03] Version 6.0.0-alpha-1
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