AWS EC2: Update Image to Ubuntu 20.04

[Engin Diri]

The VM image/os should be update to 20.04 due to this >#95

Mainly its the line

inletsctl/cmd/create.go

Line 489 in ed0bcc7

 OS:         "ubuntu/images/hvm-ssd/ubuntu-xenial-16.04-amd64-server-20191114", 

And should be tested too.

[Carlos Tadeu Panato Junior]

I will update and test it

[Engin Diri]

Done thanks @cpanato ! ❤️