docs(tutorial): fix setup-cz link - #2072

Description

Add the missing https:// scheme to the setup-cz link in the SCM release tutorial. Without the scheme, Lychee interpreted the URL as a repository-relative file path and generated repeated broken-link reports.

Checklist

• I have read the contributing guidelines

Was generative AI tooling used to co-author this PR?

• Yes (GitHub Copilot, powered by GPT-5.6 Sol)

Generated-by: GitHub Copilot following the guidelines

Code Changes

• Add test cases to all the changes you introduce
• Run uv run poe all locally to ensure this change passes linter check and tests
• Manually test the changes:
  • Verify the feature/bug fix works as expected in real-world scenarios
  • Test edge cases and error conditions
  • Ensure backward compatibility is maintained
  • Document any manual testing steps performed
• Update the documentation for the changes

Documentation Changes

• Run uv run poe doc locally to ensure the documentation pages renders correctly
• Check and fix any broken links (internal or external)

Expected Behavior

Lychee resolves the setup-cz link as an external GitHub URL instead of a missing local file.

Steps to Test This Pull Request

1. Run lychee --config lychee.toml docs/tutorials/release-scm.md.
2. Confirm both links pass with zero errors.

Additional Context

Lychee reports 2 links checked, 2 successful, and 0 errors for the affected document.

Fixes: #2071