v0.4.0

Enhancements

• Fix TypeError in pad_sequence for torch>=1.9.0 (#163)
• Make Monitor optional (#167)
• Fix for issue (#174, thanks @jfrancis71!)
• Fixed save/load problem on dqn.py (#184, thanks @jmribeiro!)

Bug fixes

• [BUGFIX] use functools.partial instead of lambda (#157, thanks @zhouzypaul!)

Documentation

• Fixes a minor typo (#161, thanks @prabhatnagarajan!)

Testing

• Fix CI error due to gym's version (#159)
• Specify the version of traitlets to fix CI error (#169)
• Fix mypy error due to numbers.Number (#171)
• Fix lint errors (#185)
• Pin pyglet==1.5.27 in CI to avoid errors (#187)