enable microgateway works with node 8.x and /node 10.x

[saywow]

node 4.x is out of service
node 6.x will be end of service next year
Please assess if microgateway will work with node 8.x and node 10.x?
Thanks

current engine in package.json

 "engines": {
    "node": ">=4.0.0"
}

should change to node >=6.0.0

[franz-josef-kaiser]

@ozairs do you have any answer here? Thanks!

[ozairs]

I will follow up with our dev team.