chore(package): update css-loader to version 0.28.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -51,7 +51,7 @@
     "colors": "^1.1.2",
     "coveralls": "^2.11.15",
     "cross-env": "^3.1.1",
-    "css-loader": "^0.26.1",
+    "css-loader": "^0.28.0",
     "enzyme": "^2.7.0",
     "express": "^4.14.0",
     "extract-text-webpack-plugin": "^1.0.1",