Got issue in BuildMarines minigame

Hi,

I ran BuildMarines mini-game with Agent that does nothing. The environment was created by this way:
`env = sc2_env.SC2Env(
map_name="BuildMarines",
step_mul=1,
visualize=False,
agent_interface_format=sc2_env.AgentInterfaceFormat(
feature_dimensions=sc2_env.Dimensions(
screen=32,
minimap=32)
)`

Sometimes SCVs are able to collect all resources from middle mineral (when appeared between mineral field and CC) for 14 min and some sec (episode lasts 15 minutes by default). And if i reset the environment then will get the bug:
This mineral will not recover and SCVs will stand still beside command center in the next episode although they should start to gather minerales themselves. It will continue until i restart the game (recreate the environment).

As workaround i use `game_steps_per_episode=16*60*14` to reduce episode time to 14 min.

I don't know is it designed so but it breaks down NN's learning process.

**PySC2**==2.0.2
**StarCraft II** is up to date.