add changelog for 0.2.0
## 0.2.0 (2019-05-21)
+**Features**
+
+ - Model DirectLineSite has a new parameter is_secure_site_enabled
+ - Model DirectLineSite has a new parameter trusted_origins
+ - Added operation group EnterpriseChannelsOperations
+
## 0.1.0 (2018-08-07)
- Initial Release
