update changelog before v4.6.0 release

Author: crodriguezvega

CHANGELOG.md

@@ -35,19 +35,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 All notable changes to this project will be documented in this file.
 
-## [[Unreleased]]
-
-### Dependencies
-
-### API Breaking
-
-### State Machine Breaking
-
-### Improvements
-
-### Features
-
-### Bug Fixes
+## [v4.6.0](https://github.com/cosmos/ibc-go/releases/tag/v4.6.0) - 2023-04-05
 
 ## [v4.5.1](https://github.com/cosmos/ibc-go/releases/tag/v4.5.1) - 2023-10-20