Update MAINTAINERS.md

[z9r5]

Description

Why do we need it, and what problem does it solve?

Why do we need it in the patch release (if we do)?

What is the expected result?

Checklist

• The code is covered by unit tests.
• e2e tests passed.
• Documentation updated according to the changes.
• Changes were tested in the Kubernetes cluster manually.

Changelog entries

section: <kebab-case of a module name> | <1st level dir in the repo>
type: fix | feature | chore
summary: <ONE-LINE of what effectively changes for a user>
impact: <what to expect for users, possibly MULTI-LINE>, required if impact_level is high ↓
impact_level: default | high | low