Try to fix drone.io builds #2

Author: fnagel

package.json

@@ -19,17 +19,17 @@
     "node": ">= 0.8.0"
   },
   "devDependencies": {
-    "grunt": "~0.4.1",
-    "load-grunt-tasks": "~3.2.0",
-    "grunt-contrib-compress": "~0.13.0",
-    "grunt-contrib-watch": "~0.6.0",
-    "grunt-contrib-csslint": "~0.1.0",
-    "grunt-contrib-cssmin": "~0.13.0",
-    "grunt-contrib-jshint": "~0.11.0",
-    "grunt-contrib-concat": "~0.5.0",
-    "grunt-contrib-uglify": "~0.9.0",
-    "grunt-contrib-clean": "~0.6.0",
-    "grunt-contrib-yuidoc": "~0.9.0",
-    "time-grunt": "~1.2.1"
+    "grunt": "^0.4.1",
+    "load-grunt-tasks": "3.2.0",
+    "grunt-contrib-compress": "^0.13.0",
+    "grunt-contrib-watch": "^0.6.0",
+    "grunt-contrib-csslint": "^0.1.0",
+    "grunt-contrib-cssmin": "^0.13.0",
+    "grunt-contrib-jshint": "^0.11.0",
+    "grunt-contrib-concat": "^0.5.0",
+    "grunt-contrib-uglify": "^0.9.0",
+    "grunt-contrib-clean": "^0.6.0",
+    "grunt-contrib-yuidoc": "^0.9.0",
+    "time-grunt": "^1.2.1"
   }
 }