got webpack production mode running

package.json

@@ -77,6 +77,7 @@
     "eslint-plugin-security": "^1.4.0",
     "expose-loader": "^0.7.5",
     "extract-loader": "^2.0.1",
+    "extract-text-webpack-plugin": "^4.0.0-beta.0",
     "fast-text-encoding": "^1.0.0",
     "file-loader": "^1.1.11",
     "fluent-intl-polyfill": "^0.1.0",
@@ -86,7 +87,6 @@
     "http_ece": "^1.0.5",
     "husky": "^0.14.3",
     "lint-staged": "^7.2.0",
-    "mini-css-extract-plugin": "^0.4.1",
     "mocha": "^5.2.0",
     "nanobus": "^4.3.2",
     "nanotiming": "^7.3.1",