dep cleanup -hiredis, node>8

package.json

@@ -38,7 +38,6 @@
     "fast-json-stable-stringify": "^2.0.0",
     "get-folder-size": "^1.0.0",
     "handlebars": "^4.0.12",
-    "hiredis": "^0.5.0",
     "hjson": "^3.1.0",
     "http-proxy": "^1.17.0",
     "js-yaml": "^3.12.0",
@@ -56,6 +55,6 @@
     "write-file-atomic": "^2.3.0"
   },
   "engines": {
-    "node": ">= 4.0.0"
+    "node": ">= 8.0.0"
   }
 }