dns/zns: Update 0.4.0 => 0.6.0

Port changes:

• Require Go 1.26+.
• Update JSON option description.
• Update pkg-descr after new features.

Changelogs:

• https://github.com/znscli/zns/releases/tag/v0.5.0
• https://github.com/znscli/zns/releases/tag/v0.6.0

Reported by: repology
Approved by: osa, vvd (Mentors, implicit)