Update asciidoctor-kroki to 0.7.0

What does this MR do and why?

Update asciidoctor-kroki gem to 0.7.0 (or latest). This ensures we're running Ruby 3 compliant code.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #372973 (closed)