Update CHANGELOG.md

Author: sunilkhedar

CHANGELOG.md

@@ -1,6 +1,7 @@
 [OST PHP SDK v1.1.1](https://github.com/OpenSTFoundation/ost-sdk-php/tree/v1.1.1) July 2 2018
 ---
 * Bug fix for V1.1 API
+* Added version file
 
 [OST PHP SDK v1.1.0](https://github.com/OpenSTFoundation/ost-sdk-php/tree/v1.1.0) July 2 2018
 ---
@@ -11,4 +12,4 @@
 [OST PHP SDK v1.0.0](https://github.com/OpenSTFoundation/ost-sdk-php/tree/v1.0.0) May 30 2018
 ---
 Initial release of the official OST PHP SDK<br />
-This release has the OST API interaction layer implementation.
+This release has the OST API interaction layer implementation.