fix: fix travis fail

Author: nurrony

.travis.yml

@@ -5,7 +5,7 @@ notifications:
 node_js:
   - '8'
 before_install: npm install --global greenkeeper-lockfile@1
-before_script: greenkeeper-lockfile-update
+before_script: npm run build && greenkeeper-lockfile-update
 after_script:
   - git diff --color | cat
   - greenkeeper-lockfile-upload