Use `gitlab-org` runner in verify jobs

This MR changes verify:install and verify:update jobs to use gitlab-org runner.

This fixes #646 (closed) where jobs fail with:

ERROR: Job failed (system failure): Cannot connect to the Docker daemon at tcp://10.142.1.25:2376. Is the docker daemon running? (executor_docker.go:782:60s)

Successful pipelines:

• https://gitlab.com/gitlab-org/gitlab-development-kit/pipelines/98233589 private-runners-manager-4.gitlab.com
• https://gitlab.com/gitlab-org/gitlab-development-kit/pipelines/98228779 private-runners-manager-3.gitlab.com
• https://gitlab.com/gitlab-org/gitlab-development-kit/pipelines/98225204 gitlab-shared-runners-manager-4.gitlab.com