Install plugin in macOS

[yevhenvolchenko]

Cannot install helm-backup plugin.
OS: macOS 10.14.3
Helm: v2.11.0

helm plugin install https://github.com/maorfr/helm-backup      
                                                                                                                                                       
Downloading and installing helm-backup  ...
https://github.com/maorfr/helm-backup/releases/download//helm-backup-macos-.tgz
tar: Unrecognized archive format
tar: Error exit delayed from previous errors.
mv: rename releases//backup to bin/backup: No such file or directory
mv: rename releases//backup.exe to bin/backup: No such file or directory
Installed plugin: backup