Improvement in default args

[JankowskiChristopher]

Hello, I have a tiny suggestion to improve the code. In train.py, the current default algo is SAC, which is a little bit counter intuitive for the CrossQ repository. My suggestion is to change it to crossq in case user forgets to change it when running.

Suggested change:

parser.add_argument("--algo", type=str, required=False, default='crossq', choices=['crossq', 'sac', 'redq', 'droq', 'td3'], help="agent to run")

side note: currently in help there is a typo - "critic activation function" instead of help related to choosing the agent.

[adityab]

Just pushed the following

• improved the argument help captions in train.py.
• set required=True on algo so people know what they're running. :wink:

Thanks for the pointers!