The long-term goal is that when "make verify" is invoked in pull job, it will
also run golangci-lint with the strict configuration and write an
$ARTIFACTS/golangci-lint-githubactions.log file with GitHub actions
annotations. How to get those published for the GitHub PR is open.
When "make verify" is invoked manually or in any other job, the stricter check
will be skipped. That works because "PR_NUMBER" is only set for pre-merge
jobs (https://github.com/kubernetes/test-infra/blob/master/prow/jobs.md#job-environment-variables).
Because strict linting is still new and might not be useful without a better
UI (= GitHub annotations), this PR does not fully enable the integration into
"make verify". Instead, the new verify-golangci-lint-pr.sh is excluded from it
and needs to be run in a separate job.
