Update actions/upload-artifact action to v4 (#10)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/upload-artifact](https://github.com/actions/upload-artifact) | action | major | `v3` -> `v4` |

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### Release Notes

<details>
<summary>actions/upload-artifact (actions/upload-artifact)</summary>

### [`v4`](https://github.com/actions/upload-artifact/compare/v3...v4)

[Compare Source](https://github.com/actions/upload-artifact/compare/v3...v4)

</details>

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### 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.

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

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Reviewed-on: #10
Co-authored-by: Renovate <renovate@kjan.de>
Co-committed-by: Renovate <renovate@kjan.de>

.gitea/workflows/CI.yaml

@@ -30,7 +30,7 @@ jobs:
       - name: Build
         run: cargo build --release
       - name: Upload artifacts
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: build
           path: target/release/passwd-cooker