Drop compatibility with v1 Vagrant boxes

[chrisroberts]

Description

Vagrant-go should eventually drop support for Vagrant V1 boxes. Currently, Vagrant-Ruby will automatically update a v1 box to a v2 box when required.

Use case (optional)

Users should receive an error message that the box version is no longer supported

Estimated task complexity time-frame (does not guarantee a delivery date)

• [x] 1 day
• [ ] 1 week
• [ ] 2-3 weeks

Estimated user impact

Minor