deps: update actions/upload-artifact action to v6 (#1276)

This PR contains the following updates:

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

---

### Release Notes

<details>
<summary>actions/upload-artifact (actions/upload-artifact)</summary>

###
[`v6`](https://redirect.github.com/actions/upload-artifact/compare/v5...v6)

[Compare
Source](https://redirect.github.com/actions/upload-artifact/compare/v5...v6)

</details>

---

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---

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.github/workflows/build.yml

@@ -23,7 +23,7 @@ jobs:
       - name: Run GoReleaser
         run: goreleaser release --clean --snapshot --skip=sign
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: Preview Binaries
           path: dist/hcloud-*/hcloud