Bump actions/download-artifact from 2 to 4 (#1811)

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 2 to 4.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](https://github.com/actions/download-artifact/compare/v2...v4)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  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/pre-release-langflow.yml

@@ -88,7 +88,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: [docker_build, release]
     steps:
-      - uses: actions/download-artifact@v2
+      - uses: actions/download-artifact@v4
         with:
           name: dist
           path: dist