Fix file naming in manifest.json

[MAILPOET-3214]

webpack.config.js

@@ -31,6 +31,7 @@ const baseConfig = {
     ],
   },
   output: {
+    publicPath: '', // This is needed to have correct names in WebpackManifestPlugin
     path: path.join(__dirname, 'assets/dist/js'),
     filename: (PRODUCTION_ENV) ? '[name].[hash:8].js' : '[name].js',
     chunkFilename: (PRODUCTION_ENV) ? '[name].[hash:8].chunk.js' : '[name].chunk.js',