chore(deps): update actions/checkout action to v5 (#16)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://github.com/actions/checkout) | action | major | `v4` -> `v5` |

---

### Release Notes

<details>
<summary>actions/checkout (actions/checkout)</summary>

### [`v5`](https://github.com/actions/checkout/compare/v4...v5)

[Compare Source](https://github.com/actions/checkout/compare/v4...v5)

</details>

---

### Configuration

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

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

♻ **Rebasing**: Whenever PR becomes conflicted, 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).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0MS41MS4xIiwidXBkYXRlZEluVmVyIjoiNDEuNTEuMSIsInRhcmdldEJyYW5jaCI6Im1haW4iLCJsYWJlbHMiOltdfQ==-->

Reviewed-on: #16
Co-authored-by: Renovate Bot <renovatebot@schulze.network>
Co-committed-by: Renovate Bot <renovatebot@schulze.network>

.gitea/workflows/lint.yml

@@ -13,7 +13,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@08eba0b27e820071cde6df949e0beb9ba4906955 # v4
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5
 
       - name: Install pnpm
         uses: pnpm/action-setup@a7487c7e89a18df4991f7f222e4898a00d66ddda # v4