add restic

[fabricionaweb]

Built from here https://slackbuilds.org/repository/15.0/system/restic/?search=restic It is most instructions in txz but uses the pre-compiled binary (official)

Restic is a backup tool similar to borg I'd say

[Mcklaren]

Hi, package added on the version 2023.03.29.

For future contributions please just add the package.slackbuild more necessary files. Packages for security reasons are only added if they are compiled by the UnRaidES team.

Thank you.