code issue in offline/cql.py

[tinnunculus]

Hello, i think there are some code lines that should be fixed in offline/cql.py.
For computing the next state action value, it seems that next_observation, not observation, should be used
Sorry... The code was actually correct, it was my mistake 😂.

[Howuhh]

@tinnunculus it's okay! CQL was the most problematic algorithm we tried, it's no surprise that it's easy to get confused with it. If you want something simple yet performant, I recommend looking at IQL/AWAC and their newer upgrades.