chore: add ref to broken horizon commit
diff --git a/roles/openstack_helm_horizon/vars/main.yml b/roles/openstack_helm_horizon/vars/main.yml
index 86bee2f..d4c6b86 100644
--- a/roles/openstack_helm_horizon/vars/main.yml
+++ b/roles/openstack_helm_horizon/vars/main.yml
@@ -39,6 +39,8 @@
           openstack_enable_password_retrieve: "True"
           # TODO(mnaser): We should drop `openstack_api_versions` once we fix the upstream change which
           #               broke it by hard-coding to "1.19" which is not a valid microversion.
+          #
+          #               https://review.opendev.org/c/openstack/openstack-helm/+/870110
           openstack_api_versions:
             container_infra: "1.10"
           raw: