Update changelog

Signed-off-by: Jacinta Ferrant <[email protected]>

Author: jferrant

stacks-signer/CHANGELOG.md

@@ -5,6 +5,16 @@ 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]
+
+### Added
+
+- Added two-phase commit to signer block responses ensuring signers only issue a signature in a BlockResponse when a majority threshold number have pre-committed to sign a proposed Naka block
+
+### Changed
+
+- Database schema updated to version 17
+
 ## [3.2.0.0.0.0]
 
 ### Added