build: bump actions/download-artifact from 6 to 7

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 6 to 7.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](https://github.com/actions/download-artifact/compare/v6...v7)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/build_publish_docker_image.yml

@@ -198,7 +198,7 @@ jobs:
 
     steps:
       - name: Download Image Digests
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           path: /tmp/digests
           pattern: digests-*