backup: create directory if it does not exist
Prior to !6837 (merged), the backup directory would be automatically created if it did not exist.
We cannot use the fileblob.CreateDir
option because this would make
the permissions of the directory world-readable and
world-writeable. Instead manually create the directory with the right
permissions.
Relates to gitlab-org/charts/gitlab#5467 (closed)
Edited by Stan Hu