update changelog before v8.3.0 release

Author: crodriguezvega

CHANGELOG.md

@@ -34,14 +34,12 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 # Changelog
 
-## [[Unreleased]]
+## [v8.3.0](https://github.com/cosmos/ibc-go/releases/tag/v8.3.0) - 2024-05-16
 
 ### Dependencies
 
 * [\#6300](https://github.com/cosmos/ibc-go/pull/6300) Bump Cosmos SDK to v0.50.6 and CometBFT to v0.38.7.
 
-### API Breaking
-
 ### State Machine Breaking
 
 * (light-clients/07-tendermint) [\#6276](https://github.com/cosmos/ibc-go/pull/6276) Fix: No-op to avoid panicking on `UpdateState` for invalid misbehaviour submissions.