[CI] Upload tune file

Author: giordano

.github/workflows/benchmark.yml

@@ -53,6 +53,11 @@ jobs:
           using BenchmarkCI
 
           BenchmarkCI.displayjudgement()
+      - uses: actions/upload-artifact@v4
+        with:
+          name: tune-json
+          path: |
+            **/tune.json
       - name: Push results
         shell: julia --color=yes {0}
         run: |