chore: upgrade Node.js to 8

DanielRuf · DanielRuf · commit 914360d550fc · 2018-05-05T22:15:55.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -19,7 +19,7 @@ env:
   global:
     - COMPOSER_BIN_DIR=~/bin
     - INTEGRATION_SETS=3
-    - NODE_JS_VERSION=6
+    - NODE_JS_VERSION=8
     - MAGENTO_HOST_NAME="magento2.travis"
   matrix:
     - TEST_SUITE=unit
