Set the seed option of the WebpackManifestPlugin to fix watch mode

Author: Lyrkan

lib/plugins/manifest.js

@@ -22,6 +22,7 @@ const manifestKeyPrefixHelper = require('../utils/manifest-key-prefix-helper');
  */
 module.exports = function(plugins, webpackConfig) {
     const manifestPluginOptions = {
+        seed: {},
         basePath: manifestKeyPrefixHelper(webpackConfig),
         // always write a manifest.json file, even with webpack-dev-server
         writeToFileEmit: true,