Running with gitlab user

What does this MR do?

Changes default 'kubesec' user to 'gitlab' user described in Use non-root users in SAST analyzers (gitlab-org/gitlab#474602 - closed) • Julian Thome • 17.6 • On track

Verification

Pipeline with current kubesec

pipeline with gitlab user kubesec (same amount of vulns) can see UID,GID in logs

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests updated/added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer