update appveyor.yml

Author: Apollon77

appveyor.yml

@@ -10,12 +10,15 @@ platform:
 clone_folder: 'c:\projects\%APPVEYOR_PROJECT_NAME%'
 install:
   - ps: 'Install-Product node $env:nodejs_version $env:platform'
+  - ps: '$NpmVersion = (npm -v).Substring(0,1)'
+  - ps: 'if($NpmVersion -eq 5) { npm install -g npm@5 }'
+  - ps: npm --version
   - npm install
 test_script:
   - echo %cd%
   - node --version
   - npm --version
-  - npm run test:unit
-  - npm run test:integration
-  - npm run test:package
+  - 'npm run test:unit'
+  - 'npm run test:integration'
+  - 'npm run test:package'
 build: 'off'