check-gotest: trigger tests on deps changes

[skhal]

Want to trigger tests for reverse deps, i.e., a change to a package A runs tests for anything that depends on it.

Example of getting a list of dependencies for a package A:

$ go list -f '{{range .Deps}}{{println . }}{{end}}' ./book/ostep/cpu/cmd/scheduler/internal/report/ | grep github.com/skhal/lab
github.com/skhal/lab/book/ostep/cpu/cmd/scheduler/internal/job
github.com/skhal/lab/book/ostep/cpu/cmd/scheduler/internal/scheduler
github.com/skhal/lab/book/ostep/cpu/cmd/scheduler/internal/sim
github.com/skhal/lab/book/ostep/cpu/cmd/scheduler/internal/trace