reset env but not set device in DeepPlace/main.py

Reset env but not set device in DeepPlace/main.py. Errors may occur when using CUDA devices.
line 148 in main.py
```
episode_rewards.append(reward)
obs = envs.reset()
features = torch.zeros(710, 2)
```
line 115 in place_env.py
```
def reset(self):
    self.obs = torch.zeros((1, 1, self.n, self.n))
    return self.obs
```
