Added the cache configuration for the eslint-loader

Author: Jeroen Meeus

lib/config-generator.js

@@ -235,6 +235,7 @@ class ConfigGenerator {
                 loader: 'eslint-loader',
                 exclude: /node_modules/,
                 enforce: 'pre',
+                cache: true,
                 options: eslintLoaderUtil.getOptions(this.webpackConfig)
             });
         }