[hotfix] fix import bug in checkpoint_io

[Fridge003]

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Fix importing bug in colossalai/checkpoint_io/utils.py

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[github-actions]

The code coverage for the changed files is 82%.

Click me to view the complete report

Name                                Stmts   Miss  Cover
-------------------------------------------------------
colossalai/checkpoint_io/utils.py     243     43    82%
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TOTAL                                 243     43    82%