Update changelog ahead of release

Author: fordN

packages/common-ts/CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Changed
+- Include AllocationExchange in NetworkContracts
 
 ## [1.8.1] - 2021-12-22
 ### Changed