Fix query is required in fetchMore

Changelog.md

@@ -17,6 +17,9 @@
   [@brentertz](https://github.com/brentertz) in [#3064](https://github.com/apollographql/react-apollo/pull/3064)
 - Stop setting optional input to `null`, when using the `graphql` HOC.  <br/>
   [@ZhengYuTay](https://github.com/ZhengYuTay) in [#3056](https://github.com/apollographql/react-apollo/pull/3056)
+- Fix typescript error caused by `query` being mandatory in the `fetchMore`
+  signature.  <br/>
+  [@HsuTing](https://github.com/HsuTing) in [#3065](https://github.com/apollographql/react-apollo/pull/3065)
 
 
 ## 2.5.6 (2019-05-22)

src/Query.tsx

@@ -27,7 +27,7 @@ export type ObservableQueryFields<TData, TVariables> = Pick<
     fetchMoreOptions: FetchMoreQueryOptions<TVariables, K> & FetchMoreOptions<TData, TVariables>,
   ) => Promise<ApolloQueryResult<TData>>) &
     (<TData2, TVariables2, K extends keyof TVariables2>(
-      fetchMoreOptions: { query: DocumentNode } & FetchMoreQueryOptions<TVariables2, K> &
+      fetchMoreOptions: { query?: DocumentNode } & FetchMoreQueryOptions<TVariables2, K> &
         FetchMoreOptions<TData2, TVariables2>,
     ) => Promise<ApolloQueryResult<TData2>>);
 };