changed to npm ci to speed tests travis

Manny Henri · Manny Henri · commit 104837c8dd82 · 2018-06-07T10:13:06.000-04:00
diff --git a/.travis.yml b/.travis.yml
@@ -4,4 +4,6 @@ node_js:
   - '8'
   - '10'
 before_install:
-- 'npm install -g npm@6'
+  - 'npm install -g npm@6'
+install:
+  - 'npm ci'
