bump fs-extra dev dep

Author: etpinard

package.json

@@ -89,7 +89,7 @@
     "ecstatic": "^1.4.0",
     "eslint": "^2.1.0",
     "falafel": "^1.2.0",
-    "fs-extra": "^0.27.0",
+    "fs-extra": "^0.28.0",
     "fuse.js": "^2.2.0",
     "glob": "^7.0.0",
     "jasmine-core": "^2.3.4",