add runner tags to review_stop job

asked in https://gitlab.com/gitlab-examples/review-apps-nginx/commit/c968a256e071dba70ae381768adfbcabe61d3d97

can you explain why review_stop job has no tags defined, what declares what runner it will use? are the runner tags inherited from "review" named job? or this is bug and the tags should be declared in review_stop as well otherwise it's unspecified in which runner the rm -rf command will be ran?

i assume there's no magic, so here's the MR to fix shortcoming