zh/docs/tasks/security/cert-management/dns-cert

[youhonglian]

Please provide a description for what this PR is for.

And to help us figure out who should review this PR, please put an X in all the areas that this PR affects.

• [ ] Configuration Infrastructure
• [X] Docs
• [ ] Installation
• [ ] Networking
• [ ] Performance and Scalability
• [ ] Policies and Telemetry
• [ ] Security
• [ ] Test and Release
• [ ] User Experience
• [ ] Developer Infrastructure

[windsonsea]

/close because it is outdated and need not to maintain again.