add py.typed to api and rocket_league subpackages for PEP 561

rlgym/rocket_league/api/car.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from dataclasses import dataclass
 from typing import Optional, Generic, Tuple
 

rlgym/rocket_league/api/game_config.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from dataclasses import dataclass
 
 from .utils import create_default_init

rlgym/rocket_league/api/game_state.py

@@ -1,6 +1,8 @@
 """
     Object to contain all relevant information about the game state.
 """
+from __future__ import annotations
+
 import numpy as np
 from dataclasses import dataclass
 from typing import Dict, Generic, Optional

rlgym/rocket_league/api/physics_object.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import numpy as np
 from dataclasses import dataclass
 from typing import TypeVar, Optional