Switch to node.js 8.

Author: XhmikosR

.travis.yml

@@ -5,7 +5,7 @@ dist: trusty
 language: node_js
 
 node_js:
-  - "6"
+  - "8"
 
 env:
   matrix:

appveyor.yml

@@ -16,8 +16,7 @@ environment:
 install:
   - SET "PATH=C:\Ruby%ruby_folder_version%\bin;%PATH%"
   - bundle install --retry 3 --jobs=%NUMBER_OF_PROCESSORS% --clean --path vendor\bundle
-  - ps: Install-Product node "6" $env:platform
-  - npm config set spin false
+  - ps: Install-Product node "8" $env:platform
   - npm install
 
 build: off
@@ -35,5 +34,5 @@ matrix:
   fast_finish: true
 
 cache:
-  - 'node_modules -> appveyor.yml,package.json'
+  - 'node_modules -> appveyor.yml,package.json,package-lock.json'
   - 'vendor\bundle -> appveyor.yml,Gemfile,Gemfile.lock'