fixed up the repo link

Author: Gareth Jones

package.json

@@ -12,7 +12,10 @@
   ],
   "license": "MIT",
   "version": "2.1.0",
-  "repository": "log4js-node/node-sandboxed-module",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/log4js-node/node-sandboxed-module.git"
+  },
   "main": "./lib/sandboxed_module",
   "files": [
     "lib/"