message: replicated fix previously mad for create to upgrade as well
diff: @@ -233,7 +233,8 @@ func upgradeRelease(cfg Config, w http.ResponseWriter, req *http.Request, params
  returnErrMessage(err, w)
  return
  }
  - appRepo, caCertSecret, authSecret, err := chart.GetAppRepoAndRelatedSecrets(chartDetails.AppRepositoryResourceName, chartDetails.AppRepositoryResourceNamespace, cfg.KubeHandler, cfg.Token, cfg.Cluster, cfg.Options.KubeappsNamespace, cfg.Options.ClustersConfig.KubeappsClusterName)
  + // TODO: currently app repositories are only supported on the cluster on which Kubeapps is installed. #1982
  + appRepo, caCertSecret, authSecret, err := chart.GetAppRepoAndRelatedSecrets(chartDetails.AppRepositoryResourceName, chartDetails.AppRepositoryResourceNamespace, cfg.KubeHandler, cfg.Token, cfg.Options.ClustersConfig.KubeappsClusterName, cfg.Options.KubeappsNamespace, cfg.Options.ClustersConfig.KubeappsClusterName)
  if err != nil {
  returnErrMessage(fmt.Errorf("unable to get app repository %q: %v", chartDetails.AppRepositoryResourceName, err), w)
  return
  