6.1.0

• 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.