GHA doesn't create release artifacts that the charts expect

[ericpromislow]

This is on BRO release/v5 v5.0.0-rc5 with the GHA changes.

make prepare VERSION=$VERSION PACKAGE=rancher-backup fails with this error message:

INFO[0000] Pulling https://github.com/rancher/backup-restore-operator/releases/download/v5.0.0-rc5/rancher-backup-5.0.0-rc5.tgz from upstream into charts
FATA[0000] encountered error while preparing main chart: encountered error while trying to pull upstream into charts: unable to read gzip formatted file: gzip: invalid header

Here are the assets for this release:

https://github.com/rancher/backup-restore-operator/releases/download/v5.0.0-rc5/backup-restore-operator_5.0.0-rc5_darwin_amd64.tar.gz
…/backup-restore-operator_5.0.0-rc5_linux_amd64.tar.gz 
…/backup-restore-operator_5.0.0-rc5_windows_amd64.tar.gz 
…/backup-restore-operator_5.0.0-rc5_darwin_arm64.tar.gz 
…/backup-restore-operator_5.0.0-rc5_linux_arm64.tar.gz 
…/backup-restore-operator_5.0.0-rc5_windows_arm64.tar.gz 

Here are the assets for the release from v4.0.2-rc1:

https://github.com/rancher/backup-restore-operator/releases/download/v4.0.2-rc1/rancher-backup-4.0.2-rc1.tgz
https://github.com/rancher/backup-restore-operator/releases/download/v4.0.2-rc1/rancher-backup-crd-4.0.2-rc1.tgz
https://github.com/rancher/backup-restore-operator/releases/download/v4.0.2-rc1/backup-restore-operator-amd64
https://github.com/rancher/backup-restore-operator/releases/download/v4.0.2-rc1/backup-restore-operator-arm64

The 4.0.2 tgz files are gzip-tarred charts, and the binaries are for linux. I guess the binary part can be fixed in the .goreleaser.yaml file, but we need a github action that tgz's the chart subdirectories.