[travis] update nodejs version

ar2rsawseen · ar2rsawseen · commit 618f776cdf7c · 2019-08-09T19:39:39.000+03:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,6 @@
 language: node_js
 node_js:
-- '6'
+- '8'
 sudo: false
 branches:
   except:
