Convert tmpdir test fixture to str after fsspec changes

[ananthsub]

What does this PR do?

Follow up to #7869
fsspec/filesystem_spec#647 in fsspec was part of the 2021.06 release recently, which checks for

from https://docs.pytest.org/en/6.2.x/tmpdir.html#the-tmpdir-fixture

tmpdir is a py.path.local object which offers os.path methods and more.

This causes the instance check to fail. As a workaround, we convert the tmpdir to str until fsspec can accommodate this again

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[codecov]

Codecov Report

Merging #7876 (cc0c795) into master (ce97676) will decrease coverage by 49%.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           master   #7876     +/-   ##
========================================
- Coverage      93%     44%    -49%     
========================================
  Files         202     202             
  Lines       13123   13121      -2     
========================================
- Hits        12156    5786   -6370     
- Misses        967    7335   +6368     

[tchaton]

Can it be done in conftest.py directly ?

[carmocca]

Tangentially related, what if we converted all tmpdir inputs to pathlib.Path in conftest?

[awaelchli]

already is a Path.
can't be convertet to str in conftest because otherwise it will fail in places where we expect tmpdir to be a Path.

[carmocca]

it is a py.path.LocalPath not a pathlib.Path, there are small differences but the latter is much more common

[carmocca]

https://stackoverflow.com/a/67027860