Remove peerDeps. Ref gruntjs/grunt#1116

Author: shama

package.json

@@ -29,14 +29,11 @@
     "grunt-contrib-jshint": "^0.11.0",
     "grunt-contrib-nodeunit": "^0.4.0"
   },
-  "peerDependencies": {
-    "grunt": ">=0.4.0"
-  },
   "keywords": [
     "gruntplugin"
   ],
   "files": [
     "tasks"
   ],
   "appveyor_id": "ybtf5vbvtenii561"
-}
+}