Add support for GPU on CI via Cirun.io

[aktech]

This is based on the discussion here: dask/community#138

• Closes GPU CI community#138
• Tests added / passed (Not applicable)
• Passes black distributed / flake8 distributed / isort distributed
• Create/Use a Cloud Account: AWS/GCP (cc @charlesbluca)
• Create an account on Cirun.io and add Cloud Credentials, Install Cirun Application on this repo and Switch the toggle on for this repository, one option is to create a bot account. (cc @charlesbluca)

This is an attempt to add support for testing distributed with GPU support on GitHub Actions via Cirun.io
Here are the tests run on my fork for reference: https://github.com/aktech/distributed/runs/2961053882?check_suite_focus=true

@quasiben It would be good to know the acceptance criteria here, It doesn't seems like the GPU tests are marked. I couldn't find a description in the docs on what are the requirements for running GPU tests, or which tests should not be skipped to be able to say GPU tests are passing, any recommendations on this?

[aktech]

Closing this one, as per @charlesbluca mentioned here dask/community#138 (comment) we'll be using gpuCI by NVIDIA.