Fixed labels_to_edges typo

[alex-1001]

No description provided.

[JoOkuma]

cc @ilan-theodoro, any guess why the API tests are failing?
They passed on #102 and this PR is a minor fix that went through our review.

[ilan-theodoro]

@JoOkuma It failed on an ome-zarr function. I checked, and the previous workflow run used ome-zarr==0.8.3, but this one is ome-zarr==0.9.0. This latter version was released a few days ago, so that is why.

I think the fix is easy (not the trivial one of pinning the package 😆) but I personally prefer to drop the dependency in favor of using iohub

[JoOkuma]

I'm all for using iohub, we can even make another PR so the segments are in ome-zarr format.
In hindsight I should have been pro it since the beginning.