chore(package): update grunt-shell to version 2.0.0 (#3642)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -77,7 +77,7 @@
     "grunt-fastly": "^0.1.3",
     "grunt-github-releaser": "^0.1.17",
     "grunt-karma": "^2.0.0",
-    "grunt-shell": "^1.3.0",
+    "grunt-shell": "^2.0.0",
     "grunt-version": "~0.3.0",
     "grunt-videojs-languages": "0.0.4",
     "grunt-zip": "0.10.2",