Prune workflows based on changed files

[KyleFromNVIDIA]

Contributes to rapidsai/build-planning#94

[jameslamb]

Changes make sense to me! I'm feeling more confident in my understanding of this workflow now.

One suggestion, and sorry I'd missed it on previous PRs in other repos... would you consider adding !.pre-commit-config.yaml to all these lists?

I'm thinking about the changes like rapidsai/build-planning#101. For those PRs where we modify pre-commit hook versions or configs, but where those modifications don't lead to any changes to e.g. Python or C++ source code files, it would be awesome to skip all test jobs.

I don't want to get too carried away with enumerating every root-level file, but think .pre-commit-config.yaml is a good candidate because it's present in almost every RAPIDS repo, and it tends to receive frequent updates.

Marking this "Approve" so that suggestion doesn't block merging, and so you can merge it without a re-review if you do implement it.

[KyleFromNVIDIA]

Thanks @jameslamb. I've added an exception for .pre-commit-config.yaml based on your feedback.

[KyleFromNVIDIA]

/merge