Add automated GPU tests

[jfowkes]

We should add CI tests that run on GPU not just CPU.

[aktech]

Allow me to jump in, GitHub Actions doesn't supports GPU runners. I created a service for the same (Cirun.io), if you want to achieve the same as in GitHub Actions On Your Cloud. Cirun is free for Open source projects as well.

Here is an example configuration from one of the projects using Cirun to give you an idea:
https://github.com/pystatgen/sgkit/blob/main/.cirun.yml

[jfowkes]

We're in the process of getting a GPU Virtual Machine that we can use to enable this.