Set "engines" requirement to node 6.0.0 (TooTallNate#82)

Krinkle · TooTallNate · commit 81574d0deabe · 2019-10-16T18:54:41.000-07:00
Follows-up from 6c804a2 and 590bc8b.
diff --git a/package.json b/package.json
@@ -31,6 +31,6 @@
     "proxy": "1.0.1"
   },
   "engines": {
-    "node": ">= 4.5.0"
+    "node": ">= 6.0.0"
   }
 }
