🛠 Make greenkeeper ignore grunt dependencies (#7463)

closes #7436

- We're moving away from grunt, so lets not worry about version bumps for now

package.json

@@ -122,7 +122,24 @@
       "glob",
       "mysql",
       "nodemailer",
-      "showdown-ghost"
+      "showdown-ghost",
+      "grunt",
+      "grunt-bg-shell",
+      "grunt-cli",
+      "grunt-contrib-clean",
+      "grunt-contrib-compress",
+      "grunt-contrib-copy",
+      "grunt-contrib-jshint",
+      "grunt-contrib-uglify",
+      "grunt-contrib-watch",
+      "grunt-docker",
+      "grunt-express-server",
+      "grunt-jscs",
+      "grunt-mocha-cli",
+      "grunt-mocha-istanbul",
+      "grunt-shell",
+      "grunt-subgrunt",
+      "grunt-update-submodules"
     ]
   }
 }