build(github-actions): Bump fsfe/reuse-action action to v6 (#374)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [fsfe/reuse-action](https://redirect.github.com/fsfe/reuse-action) |
action | major | `v5` -> `v6` |

---

### Release Notes

<details>
<summary>fsfe/reuse-action (fsfe/reuse-action)</summary>

###
[`v6`](https://redirect.github.com/fsfe/reuse-action/compare/v5...v6)

[Compare
Source](https://redirect.github.com/fsfe/reuse-action/compare/v5...v6)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - Between 08:00 AM and 04:59 PM, only on
Monday ( * 8-16 * * 1 ) (UTC), Automerge - At any time (no schedule
defined).

🚦 **Automerge**: Enabled.

♻ **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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.github/workflows/reuse-compliance.yml

@@ -16,4 +16,4 @@ jobs:
     steps:
     - uses: actions/checkout@v5
     - name: Execute REUSE Compliance Check
-      uses: fsfe/reuse-action@v5
+      uses: fsfe/reuse-action@v6