Remove breaking changes from changelog since they were rolledback before the merge.

Author: diogob

CHANGELOG.md

@@ -3,8 +3,6 @@
 ## Next release
 
 - Send close connection once the JWT token expires (if channel is open with a token using the `exp` claim).
-- Change the format of the timestamp sent with each message to use an integer value in nanoseconds.
-- Change the name of the field with the message delivery timestamp from `message_delivered_at` to `deliveredAt`.
 
 ## 0.6.1.0