BUG: Double requirement given for fsspec in requirements-dev.txt
Following error is found, while trying to set up local development environment:

ERROR: Double requirement given: fsspec>=0.7.4 (from -r requirements-dev.txt (line 69)) (already in fsspec>=0.5.1 (from -r requirements-dev.txt (line 25)), name='fsspec')

In requirements-dev.txt, two different versions of fsspec modules are specified.
fsspec>=0.5.1
fsspec>=0.7.4