Bump react-dom from 16.1.2 to 16.12.0

Bumps [react-dom](https://github.com/facebook/react/tree/HEAD/packages/react-dom) from 16.1.2 to 16.12.0.
- [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/v16.12.0/packages/react-dom)

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

package.json

@@ -43,7 +43,7 @@
     "postcss-easy-import": "3.0.0",
     "postcss-nested": "2.1.2",
     "react": "16.1.1",
-    "react-dom": "16.1.2",
+    "react-dom": "16.12.0",
     "react-redux": "5.0.6",
     "redux": "3.7.2",
     "walk": "2.3.9",