Prepare for release

Author: cressie176

CHANGELOG.md

@@ -5,7 +5,7 @@ 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
+## 3.1.0
 
 - Add support for asynchronous transports via logger.drain