Change automatic ordering when using group_tasks=True ?

[johentsch]

This is a great feature, thank you for implementing!
Is it done on purpose the the ordering of the tasks (top down) is the opposite of the Gantt charts' standard behaviour (botten up)? I tried to invert the data but apparently the tasks are automatically sorted starting on top. Is there a way to change that?

Originally posted by @laserjeyes in #588

[johentsch]

fig['layout']['yaxis'].update({'autorange': 'reversed'}) did the job.