Update changelog

CHANGELOG.md

@@ -4,8 +4,13 @@ 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]
+
+## [0.0.0] - 2019-10-21
 
 ### Added
 
 - Initial project structure, tooling, and contributing guidelines
+
+[Unreleased]: https://github.com/bhrutledge/pytest-quarantine/compare/0.0.0...HEAD
+[0.0.0]: https://github.com/bhrutledge/pytest-quarantine/releases/tag/0.0.0