deps: bump grunt-contrib libs

package.json

@@ -20,12 +20,12 @@
     "geoip-lite": "^1.3.2",
     "grunt": "^1.0.3",
     "grunt-cli": "^1.3.2",
-    "grunt-contrib-clean": "^0.6.0",
-    "grunt-contrib-concat": "^0.5.1",
-    "grunt-contrib-copy": "^0.8.0",
-    "grunt-contrib-cssmin": "^0.12.3",
-    "grunt-contrib-jade": "^0.14.1",
-    "grunt-contrib-uglify": "^0.9.1",
+    "grunt-contrib-clean": "^2.0.0",
+    "grunt-contrib-concat": "^1.0.1",
+    "grunt-contrib-copy": "^1.0.0",
+    "grunt-contrib-cssmin": "^3.0.0",
+    "grunt-contrib-jade": "^2.0.0",
+    "grunt-contrib-uglify": "^4.0.0",
     "jade": "1.11.0",
     "lodash": "3.10.1",
     "primus": "^6.0.5",