Bump actions/download-artifact from 3 to 4

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 3 to 4.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v3...v4)

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/code.yml

@@ -122,7 +122,7 @@ jobs:
         run: echo IMAGE_REPOSITORY=ghcr.io/$(tr '[:upper:]' '[:lower:]' <<< "${{ github.repository }}") >> $GITHUB_ENV
 
       - name: Download wheel and lockfiles
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           path: artifacts/
 
@@ -175,7 +175,7 @@ jobs:
       HAS_PYPI_TOKEN: ${{ secrets.PYPI_TOKEN != '' }}
 
     steps:
-      - uses: actions/download-artifact@v3
+      - uses: actions/download-artifact@v4
 
       - name: Fixup blank lockfiles
         # Github release artifacts can't be blank