chore: bump actions/download-artifact from 3.0.2 to 4.0.0 (#335)

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 3.0.2 to 4.0.0.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@9bc31d5...7a1cd32)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  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>

.github/workflows/witness.yml

@@ -50,7 +50,7 @@ jobs:
               go-version: 1.21.x
 
           - if: ${{ inputs.artifact-download != '' }}
-            uses: actions/download-artifact@9bc31d5ccc31df68ecc42ccf4149144866c47d8a # v3.0.2
+            uses: actions/download-artifact@7a1cd3216ca9260cd8022db641d960b1db4d1be4 # v4.0.0
             with:
               name: ${{ inputs.artifact-download }}
               path: /tmp