make build_images is missing permissions to download helm

[nresare]

Trying to follow the build instructions on an up-to-date Ubuntu 24.04 make build-images fails with the following error:

$ make build-images IMAGE_TAG=latest
(unset)
Downloading helm v3.15.3-gke.0
ServiceException: 401 Anonymous caller does not have storage.objects.get access to the Google Cloud Storage object. Permission 'storage.objects.get' denied on resource (or it may not exist).
make: *** [Makefile:456: "/home/noa/fun/kpt-config-sync/.output/go/bin/helm"] Error 1

Adding set -x at the top of scripts/install-helm.sh reveals the failing invocation to be gsutil cp gs://config-management-release/config-sync/helm/tag/v3.15.3-gke.0/helm-v3.15.3-gke.0-linux-amd64.tar.gz /tmp/helm-v3.15.3-gke.0-linux-amd64.tar.gz

[sdowell]

The GCS object is public but it does not allow anonymous downloads, i.e. the user must be logged in with gcloud to download the file. This is the first report we've had of this causing friction, but it's something we could potentially address

[nresare]

Oh, I see. That seems fine to me with a small addition to the build instructions. Let me propose a wording