Replace flake8 pre-commit-hook with upstream (#5892)
Replace flake8 pre-commit-hook with upstream (#5892)

See https://github.com/pre-commit/pre-commit-hooks#deprecated--replaced-hooks
jakirkham/dask,dask/dask,blaze/dask,jakirkham/dask,blaze/dask,dask/dask,mrocklin/dask,ContinuumIO/dask,mrocklin/dask,ContinuumIO/dask