Update dependency laravel/horizon to v5.8.0

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
laravel/horizon	require	minor	5.7.18 -> 5.8.0

---

Release Notes

laravel/horizon

### [`v5.8.0`](https://togithub.com/laravel/horizon/blob/HEAD/CHANGELOG.md#v580-2022-01-12-httpsgithubcomlaravelhorizoncomparev5718v580) [Compare Source](https://togithub.com/laravel/horizon/compare/v5.7.18...v5.8.0) ##### Changed - Laravel 9 Support ([#​1112](https://togithub.com/laravel/horizon/pull/1112))

---

Configuration

📅 Schedule: At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, click this checkbox.

---

This PR has been generated by WhiteSource Renovate. View repository job log here.