other(renovate): add no milestone label, include release 8.6

[ev-codes]

Description

Without this label, all Renovate PR's will fail PR check.

Dependency upgrades (especially ones handled by Renovate) clutter the release milestones more than clarifying them.

Related issues

None

Checklist

• [x] PR has a milestone or the no milestone label.

[github-actions[bot]]

Successfully created backport PR for release/8.6:

• 3314