Bug Fix
1. Add map_action_inverse for fixing the error of storing random action (568)
API Change
1. Update WandbLogger implementation and update Atari examples, use Tensorboard SummaryWritter as core with `wandb.init(..., sync_tensorboard=True)` (558, 562)
2. Rename save_fn to save_best_fn to avoid ambiguity (575)
3. (Internal) Add `tianshou.utils.deprecation` for a unified deprecation wrapper. (575)
New Features
1. Implement Generative Adversarial Imitation Learning (GAIL), add Mujoco examples (550)
2. Add Trainers as generators: OnpolicyTrainer, OffpolicyTrainer, and OfflineTrainer; remove duplicated code and merge into base trainer (559)
Enhancement
1. Add imitation baselines for offline RL (566)