Merge pull request #83 from balassy/feature/use-npm-ci

Use `npm ci` instead of `npm install` to speed up CI. See issue #76 .

Author: balassy

.travis.yml

@@ -5,7 +5,7 @@ node_js:
   - "8"
 
 before_install:
-  - npm install -g npm@5
+  - npm install -g npm@6
   - npm install -g serverless
   - npm install -g greenkeeper-lockfile@1
 

appveyor.yml

@@ -9,7 +9,7 @@ install:
   - npm install --global npm@latest
   - set PATH=%APPDATA%\npm;%PATH%
   - npm install -g serverless
-  - npm install
+  - npm ci
   - node --version
   - npm --version
 
@@ -25,4 +25,4 @@ artifacts:
   - path: .serverless
     name: Serverless Package
 
-test: off
+test: off