test(ci): test on windows and osx

[jhamman]

This PR adds CI matrix entries for OSX and Windows.

Closes #1648

Notes:

There are some interesting failures here.

- [ ] path handling in local store

• async timeout error in osx

[jhamman]

@zarr-developers/python-core-devs - do we have any Window's aficionados capable developers here? We need to do a bit of work to tweak path handling in the LocalStore and it would be approx. 1000% easier to iterate locally than via GitHub actions! The good news is that we're super close to having all the tests passing :)

[martindurant]

tweak path handling in the LocalStore

fsspec has a decent amount of work for this which you can reuse. Actually, could RemoteStore write to local too to avoid the duplication, or would that be unnecessarily complicated (given the async/sync difference in particular).

[jhamman]

fsspec has a decent amount of work for this which you can reuse.

Can you provide some pointers?

Actually, could RemoteStore write to local too to avoid the duplication, or would that be unnecessarily complicated (given the async/sync difference in particular).

I don't think this will help us because the RemoteStore requires an Async Filesystem which the fsspec local filesystem is not.

[martindurant]

fsspec calls https://github.com/fsspec/filesystem_spec/blob/master/fsspec/implementations/local.py#L284 as early as possible in localFS, since posix paths always work on windows in python (but not the other way around).

[jhamman]

I've opened a dedicated ticket for this: #2438

[jhamman]

pre-commit.ci autofix