chore: support only LTS and stable version

NoNameProvided · NoNameProvided · commit 182c693a8297 · 2017-11-11T16:35:26.000+01:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,11 +1,8 @@
 language: node_js
 node_js:
   - stable
+  - 8
   - 6
-  - 5
-  - 4
-  #- 0.12
-  #- 0.11
 
 after_success:
   - bash <(curl -s https://codecov.io/bash)
