chore(package): update mini-css-extract-plugin to version 0.5.0

Author: greenkeeper[bot]

package.json

@@ -33,7 +33,7 @@
     "dart-sass": "1.15.2",
     "fibers": "3.1.1",
     "file-loader": "2.0.0",
-    "mini-css-extract-plugin": "0.4.5",
+    "mini-css-extract-plugin": "0.5.0",
     "postcss-loader": "3.0.0",
     "sass-loader": "7.1.0",
     "stylelint": "9.9.0",