pt: support multitask finetune #6630

Job	Run time
determine-arm64-runner	1s
Build source distribution	19s
Build wheels for cp311-manylinux_x86_64	6m 18s
Build wheels for cp311-manylinux_x86_64	5m 29s
Build wheels for cp311-macosx_x86_64	9m 55s
Build wheels for cp311-macosx_arm64	4m 33s
Build wheels for cp311-win_amd64	5m 38s
Build wheels for cp310-manylinux_aarch64	5m 39s
build_docker (12)	3m 49s
build_docker (_cu11, 11)	4m 7s
build_pypi_index	10s
upload_pypi	0s
deploy_pypi_index	0s
Pass testing build wheels	4s
	46m 2s

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