Resolve "build(ynh_backup): update borg role to v.0.9.4"

Closes #79 (closed)

roles/ynh_backup/defaults/main.yml

@@ -25,7 +25,6 @@ ynh_backup:
 # Variables for YunoHost BorgBackup
 ynh_borg_backup_scheduled:            False
 m3nu_ansible_role_borgbackup_version: "v0.9.3"
-borgmatic_version:                    "1.6.5"
 borg_source_directories:
   - "/home/yunohost.backup"
 borg_repository:                      "/data/backup/borg_repository"