Bring back the Unreleased section to CHANGELOG.md

Author: daniel-niknam-envato

CHANGELOG.md

@@ -5,6 +5,8 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [Unreleased]
+
 ## [0.9.0] - 2021-10-29
 
 ### Added
@@ -122,6 +124,7 @@ or when the loop stops
 - Postgres related configuration is through `EventSourcery::Postgres.configure`
   instead of `EventSourcery.configure`.
 
+[Unreleased]: https://github.com/envato/event_sourcery-postgres/compare/v0.9.0...HEAD
 [0.9.0]: https://github.com/envato/event_sourcery-postgres/compare/v0.8.1...v0.9.0
 [0.8.1]: https://github.com/envato/event_sourcery-postgres/compare/v0.8.0...v0.8.1
 [0.8.0]: https://github.com/envato/event_sourcery-postgres/compare/v0.7.0...v0.8.0