Add changelog for ruby-grape#1868

Author: ksss

CHANGELOG.md

@@ -2,12 +2,11 @@
 
 #### Features
 
-* Your contribution here.
 * [#1864](https://github.com/ruby-grape/grape/pull/1864): Adds `finally` on the API - [@myxoh](https://github.com/myxoh).
 
 #### Fixes
 
-* Your contribution here.
+* [#1868](https://github.com/ruby-grape/grape/pull/1868): Fix NoMethodError with none hash params - [@ksss](https://github.com/ksss).
 
 ### 1.2.3 (2019/01/16)