chore(deps): update actions/checkout action to v6.0.3 (#60)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://github.com/actions/checkout) | action | patch | `v6.0.2` → `v6.0.3` |

---

### Release Notes

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

### [`v6.0.3`](https://github.com/actions/checkout/blob/HEAD/CHANGELOG.md#v603)

[Compare Source](https://github.com/actions/checkout/compare/v6.0.2...v6.0.3)

- Fix checkout init for SHA-256 repositories by [@&#8203;yaananth](https://github.com/yaananth) in [#&#8203;2439](https://github.com/actions/checkout/pull/2439)
- fix: expand merge commit SHA regex and add SHA-256 test cases by [@&#8203;yaananth](https://github.com/yaananth) in [#&#8203;2414](https://github.com/actions/checkout/pull/2414)

</details>

---

### Configuration

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

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---

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---

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Reviewed-on: #60
Reviewed-by: t.behrendt <2+t.behrendt@noreply.localhost>
Co-authored-by: Renovate Bot <renovate@t00n.de>
Co-committed-by: Renovate Bot <renovate@t00n.de>

.gitea/workflows/ci.yaml

@@ -17,7 +17,7 @@ jobs:
           - "docker-compose.json"
           - "bun-npm.json"
     steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
       - name: Validate "${{ matrix.json-file }}"
         uses: https://gitea.t000-n.de/t.behrendt/validate-json-by-json-schema-action@6bf2c1355ac4430a6fb77befd36fb95243fcaa3a # 0.1.12
         with: