Fix broken Windows target

[craffel]

Our windows target is failing (https://github.com/r-three/git-theta/actions/runs/4668786682/jobs/8266325660) with

checkout
Error: Process completed with exit code 128.

Here are some ideas on how to fix it: actions/checkout#417

[blester125]

I think this is about the checkout nd2end test not the the checkout action.

   File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\site-packages\git_theta\scripts\git_theta_filter.py", line 180, in main
    args.func(args)
  File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\site-packages\git_theta\scripts\git_theta_filter.py", line 135, in clean
    **async_utils.run(
  File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\site-packages\git_theta\async_utils.py", line 22, in run
    return asyncio.run(*args, **kwargs)
  File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\asyncio\runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\asyncio\base_events.py", line 616, in run_until_complete
    return future.result()
  File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\site-packages\git_theta\async_utils.py", line 51, in run_map
    return dict(await asyncio.gather(*(func(k, v) for k, v in mapping.items())))
  File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\site-packages\git_theta\scripts\git_theta_filter.py", line 117, in _clean
    lfs_metadata = await update_handler.write(
  File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\site-packages\git_theta\updates\dense.py", line 25, in write
    return metadata.LfsMetadata.from_pointer(lfs_pointer)
  File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\site-packages\git_theta\metadata.py", line 43, in from_pointer
    raise ValueError(f"Failed to parse pointer file {pointer_contents}")
ValueError: Failed to parse pointer file 

then there are a bunch of errors about the event loop being closes which I would assume is the loop crashing after this error happens?

Not sure what is causing the error, based on the log it seems like there isn't any pointer contents at all.

I think we'll need to spin up a windows VM to debug this, doing it via actions seems like it will take forever

[blester125]

Some more examples of when this failure occurs:

• https://github.com/r-three/git-theta/actions/runs/4668786682/jobs/8266325660#step:5:41
• https://github.com/r-three/git-theta/actions/runs/4672210342/jobs/8274136287#step:5:122
• https://github.com/r-three/git-theta/actions/runs/4765796504/jobs/8471989669#step:5:123

The issue seems to be transient as manually re-running the failed jobs seems to fix them after a while

[blester125]

Here is another example of the failure, there is more log info on this one but the issue seems to be the same
https://github.com/r-three/git-theta/actions/runs/5026793162/jobs/9015490470?pr=216#step:5:2350