fix: rclone zombie when cron backup

[exfly]

What is the purpose of this change?

Was the change discussed in an issue or in the forum before?

Checklist

• [x] I have read the contribution guidelines.
• [x] I have added tests for all changes in this PR if appropriate.
• [x] I have added documentation for the changes if appropriate.
• [x] All commit messages are in house style.
• [x] I'm done, this Pull Request is ready for review :-)

[Neustradamus]

@ncw: Have you seen this PR?

[ncw]

Can you explain what it does , what it fixes and how it works please!

[darthShadow]

tini (https://github.com/krallin/tini) is acting as a minimal process supervisor here (similar to systemd or init). Ideally, rclone should have handled the signals itself gracefully but without any logs, it's difficult to comment anything further.