Update GitHub Action workflows to actions/upload-artifact@v6 (8.5)

Author: TimWolla

.github/workflows/real-time-benchmark.yml

@@ -290,7 +290,7 @@ jobs:
           git push
       - name: Upload artifact
         if: github.event_name == 'workflow_dispatch'
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: results
           path: ./php-version-benchmarks/docs/results/${{ env.YEAR }}