Remove minimum required engine

Author: mpalourdio

package.json

@@ -61,8 +61,5 @@
     "ts-node": "~3.0.4",
     "tslint": "~5.3.2",
     "typescript": "~2.3.3"
-  },
-  "engines": {
-    "node": ">=6.0.0"
   }
 }