build(deps): bump actions/download-artifact from 4 to 8 (#8938)

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4 to 8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](https://github.com/actions/download-artifact/compare/v4...v8)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/container_release_unified.yml

@@ -168,7 +168,7 @@ jobs:
 
       - name: Download pre-built Rust binaries
         if: github.event_name != 'workflow_dispatch' || github.event.inputs.variant == 'all' || github.event.inputs.variant == matrix.variant
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v8
         with:
           pattern: rust-volume-*
           merge-multiple: true