chore(deps): bump actions/download-artifact from 4 to 8

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

Author: dependabot[bot]

.github/workflows/vib-build.yml

@@ -142,7 +142,7 @@ jobs:
         echo "IMAGE_URL=ghcr.io/$REPO_OWNER_LOWERCASE/nvidia" >> "$GITHUB_ENV"
 
     - name: Download digests
-      uses: actions/download-artifact@v4
+      uses: actions/download-artifact@v8
       with:
         path: ${{ runner.temp }}/digests
         pattern: digests-*