feat: enable perf flamegraph for walltime benches

Author: not-matthias

.github/workflows/codspeed.yml

@@ -74,5 +74,8 @@ jobs:
 
       - name: Run the benchmarks
         uses: CodSpeedHQ/action@v3
+        env:
+          CODSPEED_USE_PERF: true
         with:
           run: just run
+          runner-version: 3.6.0-beta.3