bump changelog: v1.0.0

Author: sduchesneau

CHANGELOG.md

@@ -4,7 +4,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html). See [MAINTAINERS.md](./MAINTAINERS.md)
 for instructions to keep up to date.
 
-## Unreleased
+## v1.0.0
 
 ### Added