Update build config

Author: nick-keller

.travis.yml

@@ -4,13 +4,8 @@ node_js:
 branches:
   only:
     - master
-cache:
-  directories:
-    - node_modules
 before_install:
-  - npm update
-install:
-  - npm install
+  - npm ci
 script:
   - npm test -- --coverage
   - npm run report-coverage