Update ghcr.io/twin/gatus Docker tag to v5.29.0 (#1859)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [ghcr.io/twin/gatus](https://github.com/TwiN/gatus) | minor | `v5.28.0` -> `v5.29.0` |

---

### Release Notes

<details>
<summary>TwiN/gatus (ghcr.io/twin/gatus)</summary>

### [`v5.29.0`](https://github.com/TwiN/gatus/releases/tag/v5.29.0)

[Compare Source](https://github.com/TwiN/gatus/compare/v5.28.0...v5.29.0)

#### What's Changed

- feat(metrics): Add metrics for domain expiration by [@&#8203;StefanBalea](https://github.com/StefanBalea) in [#&#8203;1244](https://github.com/TwiN/gatus/pull/1244)

#### New Contributors

- [@&#8203;StefanBalea](https://github.com/StefanBalea) made their first contribution in [#&#8203;1244](https://github.com/TwiN/gatus/pull/1244)

**Full Changelog**: <https://github.com/TwiN/gatus/compare/v5.28.0...v5.29.0>

</details>

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - 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.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

---

This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
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Reviewed-on: #1859
Co-authored-by: Renovate Bot <renovate-bot@alexlebens.net>
Co-committed-by: Renovate Bot <renovate-bot@alexlebens.net>

clusters/cl01tl/monitoring/gatus/values.yaml

@@ -7,7 +7,7 @@ gatus:
     enabled: true
   image:
     repository: ghcr.io/twin/gatus
-    tag: v5.28.0
+    tag: v5.29.0
   annotations:
     reloader.stakater.com/auto: "true"
   service: