Update CHANGELOG.md

Author: evansims

CHANGELOG.md

@@ -4,8 +4,10 @@ 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 [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## Unreleased
+
+## 1.0
 
 ### Added
 
--   Initial release.
+-   First release.