[Nostromo] Update Changelog

CHANGELOG.md

@@ -1,5 +1,10 @@
 CHANGELOG for 3.x
 =================
 
-* 3.0.0 (2017-01-xx)
+* 3.0.X (2017-XX-XX)
+ * [PR#330] Allow Composer task options to be overwritten at environment level
+ * [PR#330] Add new method Runtime::getMergedOption to merge ConfigOption and EnvOption
+ * [Documentation] [PR#333] Improve example config file
+
+* 3.0.0 (2017-01-31)
  * v3 series release