docs: use node_js 8 in example travis.yml (#4107)

nikolas2 · Timer · commit b49762ac1a24 · 2018-03-04T20:35:18.000-05:00
This is the current node LTS release.
diff --git a/packages/react-scripts/template/README.md b/packages/react-scripts/template/README.md
@@ -1611,7 +1611,7 @@ Popular CI servers already set the environment variable `CI` by default but you
 ```
 language: node_js
 node_js:
-  - 6
+  - 8
 cache:
   directories:
     - node_modules
