update changelog before v8.4.0 release

CHANGELOG.md

@@ -34,19 +34,15 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 # Changelog
 
-## [[Unreleased]]
-
-### Dependencies
-
-### API Breaking
-
-### State Machine Breaking
+## [v8.4.0](https://github.com/cosmos/ibc-go/releases/tag/v8.4.0) - 2024-07-29
 
 ### Improvements
 
+* (core/04-channel) [\#6871](https://github.com/cosmos/ibc-go/pull/6871) Add channel ordering to write acknowledgement event.
+
 ### Features
 
-* (apps/transfer) [\#6877](https://github.com/cosmos/ibc-go/pull/6877) Added the possibility to transfer the entire user balance of a particular denomination by using [`UnboundedSpendLimit`](https://github.com/cosmos/ibc-go/blob/715f00eef8727da41db25fdd4763b709bdbba07e/modules/apps/transfer/types/transfer_authorization.go#L253-L255) as the token amount.
+* (apps/transfer) [\#6877](https://github.com/cosmos/ibc-go/pull/6877) Added the possibility to transfer the entire user balance of a particular denomination by using [`UnboundedSpendLimit`](https://github.com/cosmos/ibc-go/blob/cdaaa94546af79760317f22bc93f270e3d754c84/modules/apps/transfer/types/coin.go#L60-L62) as the token amount.
 
 ### Bug Fixes