Hummingbird course YAML file

It looks like the format of the YAML file has changed. The current version in the course no longer works. After searching a bit, I found a format that works.

Code (CSharp):

1. behaviors:
2.     Hummingbird:
3.         trainer_type: ppo
4.         hyperparameters:
5.             batch_size: 2048
6.             buffer_size: 20480
7.             learning_rate: 3.0e-4
8.             beta: 5.0e-3
9.             epsilon: 0.2
10.             lambd: 0.95
11.             num_epoch: 3
12.             learning_rate_schedule: linear
13.         network_settings:
14.             normalize: false
15.             hidden_units: 256
16.             num_layers: 2
17.             vis_encode_type: simple
18.             memory_size: 128
19.             sequence_length: 64
20.             use_recurrent: false
21.         reward_signals:
22.             extrinsic:
23.                 gamma: 0.99
24.                 strength: 1.0
25.         keep_checkpoints: 5
26.         max_steps: 5.0e6
27.         time_horizon: 128
28.         summary_freq: 10000
29.         threaded: true