Update CHANGELOG.md

Author: bsideup

CHANGELOG.md

@@ -9,6 +9,7 @@ All notable changes to this project will be documented in this file.
 ### Changed
 - Added InfluxDB module ([\#686](https://github.com/testcontainers/testcontainers-java/pull/686))
 - Added MockServer module ([\#696](https://github.com/testcontainers/testcontainers-java/pull/696))
+- Changed LocalStackContainer to extend GenericContainer ([\#695](https://github.com/testcontainers/testcontainers-java/pull/695))
 
 ## [1.7.2] - 2018-04-30