Ability to resize a vdisk when deploying from image resource

[JonKohler]

from #160

The situation as reported by leonteq:

The resizing of the disk; the Ubuntu cloud image is relatively small, if we ask for the disk to be resized, it fails to resize – would be good if that could happen

Answer from Jon

We’ve fixed this in AOS 5.8.1, which should be out in 4-5 weeks. This fix missed the 5.8 shipping gate, so it will come on the next round.
When that release comes out, all you need to do is specify the disk size when you specify datasource_reference, and the API will do what you’d think it SHOULD do ☺

Scope of work here is to validate that the resizing API works as expected. Given 5.6 thru 5.9 releases are short term support, I dont suspect we need to add version-specific checking logic for this, but rather say that the provider is supported on 5.10.x++ releases, which is the next long term train now GA as of December

[marinsalinas]

I've asked to the Team if I can get a JSON example for this feature, then, I can change it using terraform configuration and test it.

[marinsalinas]

Fixed on https://github.com/terraform-providers/terraform-provider-nutanix/tree/vdisk-update-%2323