chore(deps-dev): update react requirement from 15.5.x to 15.6.x

Updates the requirements on [react](https://github.com/facebook/react) to permit the latest version.
- [Release notes](https://github.com/facebook/react/releases)
- [Changelog](https://github.com/facebook/react/blob/master/CHANGELOG.md)
- [Commits](https://github.com/facebook/react/commits/v15.6.2)

Signed-off-by: dependabot[bot] <support@dependabot.com>

package.json

@@ -69,7 +69,7 @@
     "pre-commit": "1.x",
     "rc-test": "6.x",
     "rc-tools": "6.x",
-    "react": "15.5.x",
+    "react": "15.6.x",
     "react-dom": "15.5.x",
     "react-native": "~0.42.0",
     "react-native-index-page": "~0.2.1"