Update CHANGELOG

Author: jeancochrane

CHANGELOG.md

@@ -5,6 +5,10 @@ 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
+
+- Support SQLAlchemy 1.3 by adjusting the mock for threadlocal engine strategy [\#15](https://github.com/jeancochrane/pytest-flask-sqlalchemy/pull/15)
+
 ## [1.0.1](https://github.com/jeancochrane/pytest-flask-sqlalchemy/releases/tag/v1.0.1) (2019-03-02)
 
 ### Changed