Helm Spray does not support chart reference

[jroucheton]

Platform

Version of helm: v2.16.1
Version of helm-spray: v3.4.5

What happened?

helm spray my-repo/my-chart
[spray] fetching chart "my-repo/my-chart" from repos...
Error: chart "my-chart" matching version "" not found in incubator index. (try 'helm repo update'). No chart version found for my-chart

What you expected to happen?

helm spray should be able to download the latest version from my repo as helm install does.
helm install my-repo/my-chart