update for 0.8.4

Author: knonomura

package.json

@@ -7,7 +7,7 @@
   },
   "gypfile": true,
   "name": "griddb-node-api",
-  "version": "0.8.1",
+  "version": "0.8.4",
   "description": "Node API for GridDB",
   "author": "TOSHIBA Digital Solutions Corporation",
   "license": "Apache-2.0"