chore: bump signer changelog

Author: jcnelson

stacks-signer/CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to the versioning scheme outlined in the [README.md](README.md).
 
-## [Unreleased]
+## [3.1.0.0.4.0]
 
 ## Added