Replace fcntl for Windows compatibility

[monatis]

When I installed the package and ran the first command with colab auth login on Windows, it fails with "no module named fcntl". As I can see from the code, it's used for file locking operations:

google-colab-cli/src/colab_cli/state.py

Lines 66 to 80 in 510115b

	with open(self.path, "r") as f:
	fcntl.flock(f, fcntl.LOCK_SH)
	try:
	yield f
	finally:
	fcntl.flock(f, fcntl.LOCK_UN)
	@contextlib.contextmanager
	def _lock_exclusive(self) -> Iterator[IO]:
	with open(self.path, "a+") as f:
	fcntl.flock(f, fcntl.LOCK_EX)
	try:
	yield f
	finally:
	fcntl.flock(f, fcntl.LOCK_UN)

It can be replaced with filelock, which is cross-platform, or import winfcntl conditionally on Windows. I can raise a PR if it's ok to you.

[teeler]

just a note that colab auth login is not a real command (colab auth is, but in our experience it doesn't do what users think it does, so it's hidden at the moment)

[teeler]

Thanks for raising the issue otherwise - we're not targeting windows at the moment but will flag this bug for windows support when we get a chance to prioritize it.

[monatis]

we're not targeting windows at the moment

Sad. I'm a regular Windows user and really want to use Colab CLI personally in my machine. If it's just a capacity issue on your end, I can happily work on it end-to-end. I'm a GDE, btw.

[monatis]

I implemented Windows support in my fork.