add lts plus latest node version to travis build

Maciej Warszawski · Maciej Warszawski · commit 023f117aa47f · 2018-02-13T02:36:08.000+01:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,8 @@
 language: node_js
 node_js:
-  - "lts/*"
+  - "6"
+  - "8"
+  - "9"
 cache:
   directories:
     - "node_modules"
