Add Support for Vultr Serverless Inference

[christhemorse]

Description

With the beta launch of Vultr Serverless Inference, this PR was put together to ensure this product is supported in our Go library.

Checklist:

• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• [x] Have you linted your code locally prior to submission?
• [x] Have you successfully ran tests with your changes locally?