./src/createNavigationContainer -> @react-navigation/native/src/createAppContainer on NavigationTestUtils.js (#5266)

* ./src/createNavigationContainer deprecated , so change.

* changelog

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+- fix NavigationTestUtils.js deprecated file import.
+
 - Update `getParam` flow typings to check `key` and `fallback` arguments, as well as return the correct type automatically.
 
 ## [2.17.0] - [2018-09-25](https://github.com/react-navigation/react-navigation/releases/tag/2.17.0)

NavigationTestUtils.js

@@ -1,4 +1,4 @@
-import { _TESTING_ONLY_reset_container_count } from './src/createNavigationContainer';
+import { _TESTING_ONLY_reset_container_count } from '@react-navigation/native/src/createAppContainer';
 
 export default {
   resetInternalState: () => {