adjustment to tune ppo

sandbox/multicolumn/tune_ppo.py

@@ -191,7 +191,7 @@ class TrialCallback(BaseCallback):
 def objective(trial: optuna.Trial) -> float:
     n_eval_episodes = 10
     eval_freq = 5000
-    n_steps = 100000
+    n_steps = 250000
 
     with tempfile.TemporaryDirectory() as log_dir:
         env = DummyVecEnv([