Automate Grafana k6 release notes

[inancgumus]

What

Automate the manual process of adding links to the k6 release notes.

Issue

Looking at the release notes, it stops at v0.57.0.

Why

• To make it less error-prone by avoiding us from forgetting to update.
• Users can see release notes consistently.

Originaly proposed by: @mem 🙇