update zombie config

config/ppo/Zombie.yaml

   PushBlock:
     trainer_type: ppo
     hyperparameters:
-      batch_size: 128
-      buffer_size: 2048
+      batch_size: 1024
+      buffer_size: 10240
-      lambd: 1.0
+      lambd: 0.95
-      num_layers: 3
+      num_layers: 2
       vis_encode_type: simple
     reward_signals:
       extrinsic:
     time_horizon: 64
     summary_freq: 10000
     threaded: true
+env_settings:
+  num_envs: 3