Fix travis build

Update package-lock.json

Author: voodooattack

.travis.yml

@@ -2,6 +2,10 @@ language: nodejs
 
 node_js: 8.12.0
 
+cache:
+  directories:
+  - node_modules
+
 before_script:
 - npm install
 - npm run build
@@ -30,6 +34,7 @@ deploy:
 - provider: npm
   email: [email protected]
   api_key: $NPM_TOKEN
+  skip_cleanup: true
   on:
     tags: true
     repo: voodooattack/when-ts