Make the --ssl-capath CLI argument a directory

[rolandwalker]

Description

This influences the helpdoc, which now will show

--ssl-capath DIRECTORY

Checklist

• I added this contribution to the changelog.md file.
• I added my name to the AUTHORS file (or it's already there).
• To lint and format the code, I ran

  uv run ruff check && uv run ruff format && uv run mypy --install-types .

[github-actions]

Findings
No correctness or security issues found in the change.

Missing Tests / Edge Cases

1. Add a CLI test to assert --ssl-capath rejects files and non-existent paths and accepts existing directories. This prevents regressions in validation behavior. Reference: mycli/main.py:1666.

Notes

• The help text showing DIRECTORY is consistent with Click’s directory type name.

If you want, I can draft the test.