renovate bot not proposing metallb upgrades

We have:

units:
  metallb:
    ...
    helm_repo_url: https://metallb.github.io/metallb
    helmrelease_spec:
      chart:
        spec:
          chart: metallb
          version: 0.13.12

https://gitlab.com/sylva-projects/sylva-core/-/blob/dcf193af92ae742f3d8aecee11660d186102204f/charts/sylva-units/values.yaml?page=3#L2078-2083

But the Renovate Bot is not proposing any upgrade for metallb.

Even though there are much more recent versions available:

$ helm show chart metallb/metallb
apiVersion: v2
appVersion: v0.14.3
dependencies:
- condition: crds.enabled
  name: crds
  repository: ""
  version: 0.14.3
- condition: frrk8s.enabled
  name: frr-k8s
  repository: https://metallb.github.io/frr-k8s
  version: 0.0.8
description: A network load-balancer implementation for Kubernetes using standard
  routing protocols
home: https://metallb.universe.tf
icon: https://metallb.universe.tf/images/logo/metallb-white.png
kubeVersion: '>= 1.19.0-0'
name: metallb
sources:
- https://github.com/metallb/metallb
type: application
version: 0.14.3

/cc @loic.nicolle