Enforce consistent formatting as part of GitHub Actions workflow

[romanc]

Consistent formatting is important to avoid unnecessary conflicts and keep a consistent style in a shared codebase. Contribution guidelines thus kindly ask to run yapf before/when submitting a PR. However, consistent formatting isn't enforced in GHA workflows.

Given that two small PRs ^{1 2} showed formatting changes in code parts that I didn't touch, I would like to start a discussion on automatically enforcing consistent formatting as part of the GitHub Actions workflow.

I am happy to provide a PR for such a workflow early next year assuming we come to an agreement in this discussion.

Footnotes

1. https://github.com/spcl/dace/pull/1731 ↩

2. https://github.com/spcl/dace/pull/1803 ↩

[romanc]

PR to show how this could look like: #1957