ci: bump actions/download-artifact from 5.0.0 to 6.0.0 (#17719)

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](https://github.com/actions/download-artifact/compare/634f93cb2916e3fdff6788551b99b062d0335ce0...018cc2cf5baa6db3ef3c5f8a56943fffe632ef53)

---
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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/ci-api-docs.yml

@@ -67,7 +67,7 @@ jobs:
       - build
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5
-      - uses: actions/download-artifact@634f93cb2916e3fdff6788551b99b062d0335ce0 # v5
+      - uses: actions/download-artifact@018cc2cf5baa6db3ef3c5f8a56943fffe632ef53 # v5
         with:
           name: api-docs
           path: website/api/build