Allow to run helper image within GCP cluster with enable BinAuth
Description
Helper image is specified without registry (docker.io
): https://gitlab.com/gitlab-org/gitlab-runner/blob/222cd6ef46e04c70cabc9a5bcbb93449d5e7f2c0/helpers/docker/helperimage/info.go#L13
Which prevents it from running on GCP cluster with enabled BinAuth even if it's whitelisted.
Proposal
Add docker.io
to the default helper image url