chore(deps): bump actions/download-artifact from 5 to 6 (#2642)

Author: dependabot[bot]

.github/workflows/benchmark.yml

@@ -91,7 +91,7 @@ jobs:
         run: uv pip install seaborn
 
       - name: Download all artifacts
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           path: autotest/.benchmarks