Class-scoped fixture as instance method pytest deprecations

[smorken]

some of the usages of test fixtures will be deprecated as of pytest version 9.1 and will break as of pytest version 10.0

for example:

filesystem_spec/fsspec/tests/abstract/__init__.py

Line 21 in 65d58d4

@pytest.fixture

pytest deprecations:
https://docs.pytest.org/en/stable/deprecations.html#class-scoped-fixture-as-instance-method