Update actions/setup-node action to v6

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [ghcr.io/renovatebot/renovate](https://renovatebot.com) ([source](https://github.com/renovatebot/renovate)) | container | major | `41` -> `42` |

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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.

---

 - [ ] <!-- 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:eyJjcmVhdGVkSW5WZXIiOiI0MS4xNzEuNCIsInVwZGF0ZWRJblZlciI6IjQxLjE3MS40IiwidGFyZ2V0QnJhbmNoIjoibWFpbiIsImxhYmVscyI6W119-->

Reviewed-on: #77
Co-authored-by: Renovate Bot <renovate-bot@alexlebens.net>
Co-committed-by: Renovate Bot <renovate-bot@alexlebens.net>

.gitea/workflows/renovate.yaml

@@ -13,7 +13,7 @@ on:
 jobs:
   renovate:
     runs-on: ubuntu-latest
-    container: ghcr.io/renovatebot/renovate:41
+    container: ghcr.io/renovatebot/renovate:42
     steps:
       - name: Checkout
         uses: actions/checkout@v4

.gitea/workflows/test-build.yaml

@@ -22,7 +22,7 @@ jobs:
           version: 10.x
 
       - name: Set up Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 22.21.1
           cache: pnpm