chore(package): update stylelint-config-standard to version 20.0.0

Closes #355

Author: greenkeeper[bot]

package.json

@@ -109,7 +109,7 @@
     "start-server-webpack-plugin": "^2.2.1",
     "style-loader": "^0.20.2",
     "stylelint": "^9.0.0",
-    "stylelint-config-standard": "^18.1.0",
+    "stylelint-config-standard": "^20.0.0",
     "url-loader": "^0.6.2",
     "webpack": "^3.11.0",
     "webpack-assets-manifest": "^1.0.0",