Bump actions/download-artifact from 5 to 6 (#20787)

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](https://github.com/actions/download-artifact/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '6'
  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/docker.yml

@@ -134,7 +134,7 @@ jobs:
         run: |
           cp ./docker/prod/Dockerfile ./Dockerfile
       - name: Download precompiled public assets
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: public-assets-${{ inputs.tag }}-${{ github.sha }}
           path: public/
@@ -285,7 +285,7 @@ jobs:
           overwrite: true
           name: "merged-digests-${{ inputs.tag }}-${{ matrix.target }}-${{ github.run_number }}-${{ github.run_attempt }}"
       - name: Download digests
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: "merged-digests-${{ inputs.tag }}-${{ matrix.target }}-${{ github.run_number }}-${{ github.run_attempt }}"
           path: /tmp/digests