fix(travis): apply workaround travis-ci/travis-ci#8836

Walker Leite · Walker Leite · commit 9f5285be6c1b · 2018-02-20T18:16:10.000-03:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,4 +1,5 @@
 language: node_js
+sudo: required
 node_js:
   - "8"
   - "node"
