setup: Use kpet's new --targeted-sources option

Use the new --targeted-sources option for kpet run source list, instead of the old --targeted option, which changed meaning and effect to controlling tests included into the run, instead of controlling the output sources.

This fixes targeted status calculation for the run.

Without this change, most pipelines and tested MRs would get "untargeted" status, as the command would output all source files most of the time, because the option's effect would only be to exclude untargeted tests from the last execution (for the last architecture) in the run, and not filter the source files in any way.

TLDR: I forgot to update the pipeline to match kpet!254 (merged)