chore(package): update grunt-accessibility to version 5.0.0 (#3747)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -66,7 +66,7 @@
     "ghooks": "^1.3.2",
     "gkatsev-grunt-sass": "^1.1.1",
     "grunt": "^0.4.4",
-    "grunt-accessibility": "^4.1.0",
+    "grunt-accessibility": "^5.0.0",
     "grunt-babel": "^6.0.0",
     "grunt-banner": "^0.4.0",
     "grunt-browserify": "3.5.1",