Bump actions/download-artifact from 5.0.0 to 6.0.0

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 5.0.0 to 6.0.0.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@634f93c...018cc2c)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/update_manifests.yml

@@ -131,7 +131,7 @@ jobs:
       - run: rm -rf /tmp/manifest_updater
       - run: mkdir /tmp/manifest_updater
       - run: chmod 700 /tmp/manifest_updater
-      - uses: actions/download-artifact@634f93cb2916e3fdff6788551b99b062d0335ce0 # v5.0.0
+      - uses: actions/download-artifact@018cc2cf5baa6db3ef3c5f8a56943fffe632ef53 # v6.0.0
         with:
           path: /tmp/manifest_updater/download_artifacts
       - run: mv /tmp/manifest_updater/download_artifacts/manifest_file_for_*/Manifest-v*.toml .ci