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

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://github.com/actions/checkout) | action | digest | `08c6903` -> `93cb6ef` |

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### 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.

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 - [ ] <!-- 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).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0Mi4xMS4wIiwidXBkYXRlZEluVmVyIjoiNDIuMTEuMCIsInRhcmdldEJyYW5jaCI6Im1haW4iLCJsYWJlbHMiOltdfQ==-->

Reviewed-on: #46
Co-authored-by: Renovate Bot <renovatebot@schulze.network>
Co-committed-by: Renovate Bot <renovatebot@schulze.network>

.gitea/workflows/renovate.yaml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     container: ghcr.io/renovatebot/renovate:latest@sha256:c6950364d634f956a88238f46510f6a9a77809f3d4427c68110b7bd750afc759
     steps:
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5
+      - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6
       - run: renovate
         env:
           RENOVATE_CONFIG_FILE: "/workspace/renovate-bot/renovate-config/config.js"