Bump actions/download-artifact from 5 to 6 (#6382)

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/ccpp.yml

@@ -188,7 +188,7 @@ jobs:
       - id: upload-url
         run: |
           echo "url=$(cat create-release/release_upload_url.txt)" >> $GITHUB_OUTPUT
-      - uses: actions/download-artifact@v5
+      - uses: actions/download-artifact@v6
         with:
           name: 'assimp-bins-${{ matrix.name }}-${{ github.sha }}'
       - uses: actions/upload-release-asset@v1