chore(package): update normalize.css to version 5.0.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -22,7 +22,7 @@
     "dom101": "1.3.0",
     "github-markdown-css": "2.4.1",
     "iconfonts": "0.9.0",
-    "normalize.css": "4.2.0",
+    "normalize.css": "5.0.0",
     "nprogress": "0.2.0",
     "onmount": "1.3.0",
     "pjax": "0.2.4",