Fix CHANGELOG

Author: gpahal

CHANGELOG.md

@@ -12,7 +12,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 - **[BREAKING]** Optional `metadata` parameter of type `grpc.Metadata` to the
   `DgraphClientStub` methods. `options` parameter moved to the third position
-  to conform with the `grpc` package API.
+  to conform to the `grpc` package API.
 
   Methods affected - `DgraphClient#alter`, `Txn#query`, `Txn#queryWithVars`,
   `Txn#mutate`, `Txn#commit` and `Txn#discard`.