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

Closes #154

Author: greenkeeper[bot]

package.json

@@ -90,7 +90,7 @@
     "sass-loader": "^7.1.0",
     "style-loader": "^0.23.1",
     "stylelint": "9.10.1",
-    "stylelint-config-standard": "^18.2.0",
+    "stylelint-config-standard": "^20.0.0",
     "url-loader": "1.1.2",
     "webpack": "4.29.0",
     "webpack-cli": "3.2.1",