GPU CI

[slayoo]

Dear @atmos-cloud-sim-uj/pysdm-users.

Thanks to @Delcior, we have now a way of executing the PySDM testsuite on GPU-equipped hardware through a self-hosted GithubActions runner set up at the Jagiellonian University.

We have faced some obstacles setting up the the workflow:

• GitHub discourages usage of self-hosted runners for public repos,
• private repos cannot constitute forks of public repos on GitHub,
• PRs cannot be made across non-forked repos on Github.

The steps to use the new infrastructure are thus as follows:

• request read permissions to the following private repo: github.com/Delcior/PySDM-GPU-CI
• create your own fork of the above repo
• manually set it as a remote and push from your local PySDM repo
• create a PR to Delcior/PySDM-GPU-CI and check if tests are OK on the GPU workflow

We'll aim at streamlining the workflow in near future. For now, kudos @Delcior for making it work!