Support 'node-webkit' target

This will allow to populate manually predefined global var "__VUE_SSR_CONTEXT__" on server side rendering in php/v8js

Author: alfredriesen

lib/index.js

@@ -53,7 +53,7 @@ module.exports = function (source) {
   const incomingQuery = qs.parse(rawQuery)
   const options = loaderUtils.getOptions(loaderContext) || {}
 
-  const isServer = target === 'node'
+  const isServer = target === 'node' || target === 'node-webkit'
   const isShadow = !!options.shadowMode
   const isProduction = options.productionMode || minimize || process.env.NODE_ENV === 'production'
   const filename = path.basename(resourcePath)