package.json: Update the "engine" field

* Use just 0.10 instead of 0.10.0 (it's shorter).

  * Remove space after >= (it is apparently conventionally not used in
    the npm world).

package.json

@@ -52,6 +52,6 @@
     "jshint": "2.8.0"
   },
   "engines": {
-    "node": ">= 0.10.0"
+    "node": ">=0.10"
   }
 }