chore: cl release v231 (#1795)

Author: RafilxTenfen

CHANGELOG.md

@@ -37,6 +37,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ## Unreleased
 
+## v2.3.1
+
+### Improvements
+
+- [#1775](https://github.com/babylonlabs-io/babylon/pull/1775) testnet: add upgrade `v23` to testnet build tag
+for bbn-test-6
+
 ## v2.3.0
 
 ### Improvements