chore(build): upgrade devDependencies

Upgrade dependencies that are safe to upgrade with no changes needed
in any configuration.

package.json

@@ -9,20 +9,20 @@
     "url": "https://github.com/angular-ui/bootstrap.git"
   },
   "devDependencies": {
-    "grunt": "~0.4.1",
-    "grunt-ngdocs": "~0.1.1",
+    "grunt": "^0.4.5",
+    "grunt-contrib-concat": "^0.5.1",
+    "grunt-contrib-copy": "^0.8.0",
+    "grunt-contrib-jshint": "^0.11.1",
+    "grunt-contrib-uglify": "^0.8.0",
+    "grunt-contrib-watch": "^0.6.1",
     "grunt-conventional-changelog": "^1.1.0",
-    "grunt-contrib-concat": "~0.3.0",
-    "grunt-contrib-copy": "~0.5.0",
-    "grunt-contrib-uglify": "~0.3.0",
-    "grunt-contrib-watch": "~0.5.0",
-    "grunt-contrib-jshint": "~0.8.0",
-    "grunt-html2js": "~0.2.0",
+    "grunt-ddescribe-iit": "0.0.6",
+    "grunt-html2js": "^0.3.0",
+    "grunt-ngdocs": "~0.1.1",
     "grunt-karma": "~0.4.4",
     "node-markdown": "0.1.1",
     "semver": "~2.2.0",
-    "shelljs": "~0.2.0",
-    "grunt-ddescribe-iit": "0.0.4"
+    "shelljs": "^0.4.0"
   },
   "license": "MIT"
 }