Replace FSTimeoutError with parent TimeoutError
PR #3050 introduced a dependency on `fsspec.FSTiemoutError`. Note that this error only exists from `fsspec` version `2021.06.0` (June 2021).

To fix #3097, there are 2 alternatives:
- Either pinning `fsspec` to versions newer or equal to `2021.06.0`
- Or replacing `fsspec.FSTimeoutError` wth its parent `asyncio.TimeoutError`, which exists from Python 3.8.0 (Sep 2018).

This PR implements the second approach.

Fix #3097.