npm: update grunt-contrib-clean to 1.0.0

- Drop support for Node.js v0.8.
- Grunt peer dependency tagged `>= 0.4.5`.
- Dependency updates.

ref: https://github.com/gruntjs/grunt-contrib-clean/blob/master/CHANGELOG

package.json

@@ -19,7 +19,7 @@
     "grunt": "^1.0.0",
     "grunt-bump": "0.8.0",
     "grunt-cli": "^1.2.0",
-    "grunt-contrib-clean": "0.7.0",
+    "grunt-contrib-clean": "^1.0.0",
     "grunt-contrib-copy": "0.8.2",
     "grunt-contrib-jshint": "0.11.3",
     "grunt-contrib-uglify": "0.11.0",