Bump actions/download-artifact from 4 to 5 (open-telemetry#576)

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4 to 5.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v4...v5)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Tom Tan <[email protected]>

Author: dependabot[bot]

.github/workflows/nginx.yml

@@ -36,7 +36,7 @@ jobs:
         run: |
           mkdir artifacts
       - name: Download artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v5
         with:
           path: artifacts
           merge-multiple: true