Bump Kubectl and Helm in Auto-DevOps.gitlab-ci.yml

What does this MR do?

• Bumps Kubectl from 1.11.7 to 1.11.9 (https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.11.md#changelog-since-v1117)
• Bumps Helm from 2.12.3 to 2.13.1 (https://github.com/helm/helm/releases/tag/v2.13.0 and https://github.com/helm/helm/releases/tag/v2.13.1)

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/52791

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [-] Documentation created/updated via this MR
• [-] Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• [-] Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• [-] Conforms to the database guides
• [-] Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer