Update node-sass to the latest version 🚀 (#1065)

* chore(package): update node-sass to version 4.12.0

* chore(package): update lockfile package-lock.json

Author: greenkeeper[bot]

package-lock.json

@@ -71,7 +71,7 @@
     "jest-cli": "23.2.0",
     "js-beautify": "1.9.1",
     "marked": "0.6.2",
-    "node-sass": "4.9.3",
+    "node-sass": "4.12.0",
     "parse": "2.3.2",
     "path-to-regexp": "3.0.0",
     "prismjs": "1.16.0",