update changelog

Author: tiagoschenkel

CHANGELOG.md

@@ -18,6 +18,12 @@
 
 ## Signals 0.2.0
 
+### v0.2.1
+
+- Update `karma` setup to generate code coverage report only for `src` folder (see #78).
+
+- Update dev dependencies to latest version.
+
 ### [v0.2.0](https://github.com/RobotlegsJS/SignalsJS/releases/tag/0.2.0) - 2018-08-02
 
 - Adds copyright notice (see #74).