update package.json file to support node 9.x (#1508)

* update package.json file to support node 9.x

Some of use are using node 9.x

* Allow all node versions >= 6.x

Author: simcoder

package.json

@@ -19,7 +19,7 @@
     "graphql-js"
   ],
   "engines": {
-    "node": "6.x || 8.x || >= 10.x"
+    "node": ">= 6.x"
   },
   "scripts": {
     "watch": "node ./resources/watch.js",