v0.2.6
[engine] fixed bug in gradient accumulation dataloader to keep the last step (#1030)
[NFC] polish colossalai/engine/gradient_handler/utils.py code style (#2708)
[NFC] polish colossalai/engine/schedule/_pipeline_schedule.py code style (#2744)
fix format (#580)
[doc] add deepspeed citation and copyright (#2996)