Make default network match sb3

Author: RunnersNum40

oryx/policy/actor_critic/mlp.py

@@ -44,7 +44,7 @@ def __init__(
         *,
         feature_size: int = 64,
         feature_width: int = 64,
-        feature_depth: int = 2,
+        feature_depth: int = 0,
         value_width: int = 64,
         value_depth: int = 2,
         action_width: int = 64,