Use rake 13.0.x

What does this MR do?

Upgrade rake from 12.2 to 13.0 to avoid SNYK-RUBY-RAKE-552000 (CVE-2020-8130) on rubocop job in CI.

After

https://gitlab.com/gitlab-org/charts/gitlab/-/jobs/2459762632

Related issues

n/a

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion.

Required

• Merge Request Title and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• [n/a] Documentation created/updated
• [n/a] Tests added
• [n/a] Integration tests added to GitLab QA
• [n/a] Equivalent MR/issue for omnibus-gitlab opened