chore: fix tests

Author: satazor

.travis.yml

@@ -5,8 +5,9 @@ node_js:
   - '5.6'
   - '5.7'
   - '6'
-  - 'node'
   - 'lts/*'
+# nodejs 11.11.X was failing with this https://travis-ci.org/moxystudio/node-proper-lockfile/jobs/503161746#L469
+#  - 'node'
 after_success:
   - "npm i codecov"
   - "node_modules/.bin/codecov"