Update appveyor.yml

appveyor.yml

@@ -1,4 +1,13 @@
-# branches to build
+# Test against the latest version of this Node.js version
+environment:
+  nodejs_version: "6"
+
+# Install scripts. (runs after repo cloning)
+install:
+  # Get the latest stable version of Node.js or io.js
+  - ps: Install-Product node $env:nodejs_version
+  # install modules
+  - npm install
 
 # configuration for "master" branch
 # build in Release mode and deploy to Azure
@@ -6,7 +15,7 @@
   branches:
     only:
       - master
-  image: Visual Studio 2015
+  image: Visual Studio 2017
   environment:
     DOTNET_CLI_TELEMETRY_OPTOUT: true
     DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true