chore(deps): update actions/checkout action to v6 (#8)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://github.com/actions/checkout) | action | major | `v5` → `v6` |

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### Release Notes

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

### [`v6`](https://github.com/actions/checkout/blob/HEAD/CHANGELOG.md#v602)

[Compare Source](https://github.com/actions/checkout/compare/v5...v6)

- Fix tag handling: preserve annotations and explicit fetch-tags by [@&#8203;ericsciple](https://github.com/ericsciple) in [#&#8203;2356](https://github.com/actions/checkout/pull/2356)

</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 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

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This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
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Co-authored-by: t.behrendt <t.behrendt@t00n.de>
Reviewed-on: #8
Reviewed-by: t.behrendt <t.behrendt@noreply.localhost>
Co-authored-by: Renovate Bot <renovate@t00n.de>
Co-committed-by: Renovate Bot <renovate@t00n.de>

.gitea/workflows/cd.yaml

@@ -10,7 +10,7 @@ jobs:
     name: Release
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           fetch-depth: 0
       - name: Increment tag

.gitea/workflows/ci.yaml

@@ -8,7 +8,7 @@ jobs:
     name: Dry-Run
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       - name: Validate JSON
         uses: ./
         with:

.gitea/workflows/prerelease.yaml

@@ -8,7 +8,7 @@ jobs:
     name: Release
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           fetch-depth: 0
       - name: Increment tag