markdownlint-cli2 plugin is not installed in compile:gitaly job

Overview

https://gitlab.com/gitlab-org/gitlab-development-kit/-/jobs/8007439036 failed because the markdownlint-cli2 asdf plugin is not installed. We need to install it there.

Impacted categories

The following categories relate to this issue:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.