update syntax for webpack arguments (#101)

Author: mchoun

package.json

@@ -22,7 +22,7 @@
     "clean": "rimraf dist coverage",
     "reinstall": "rimraf flow-typed && rimraf node_modules && npm install && flow-typed install",
     "debug": "cross-env NODE_ENV=debug",
-    "webpack": "babel-node --plugins=transform-es2015-modules-commonjs ./node_modules/.bin/webpack --progress",
+    "webpack": "babel-node --plugins=transform-es2015-modules-commonjs ./node_modules/.bin/webpack -- --progress",
     "eslint-find-rules": "eslint-find-rules --current .eslintrc.js --unused --plugin",
     "prepare": "husky install"
   },