CHANGELOG.md: Added information about version 1.5.6

Author: Taritsyn

CHANGELOG.md

@@ -4,6 +4,9 @@ Change log
 ## December 3, 2015 - v1.6.0
  * Added support of “Edge” JsRT version of Chakra JavaScript engine
  * `ChakraJsRt` mode was renamed to `ChakraIeJsRt`
+ 
+## July 23, 2015 - v1.5.6
+ * Source code of the `ChakraJsRtJsEngine` was synchronized with the Chakra Sample Hosts version of July 11, 2015
 
 ## June 29, 2015 - v1.5.5
  * Fixed an error, that occurs on computers with IE 6