ZipStore fails to handle scalar string arrays

Minimal, reproducible code sample, a copy-pastable example if possible

import zarr
import numpy as np
name = 'hello'
data = np.array('world', dtype='<U5')
store = zarr.ZipStore('test_store.zip', mode='w')
root = zarr.open(store , mode='w')
zarr_array = root.create_dataset(name, data=data, shape=data.shape, dtype=data.dtype)
zarr_array[...]

# zarr_array = root.create_dataset(name, shape=data.shape, dtype=data.dtype)
# root[name][...] = data
# zarr_array[...]

Problem description

Scalar coordinates are useful as coordinates in xarray and likely other situations. Serializing them in zarr in a zipstore would be cool!.

xref: https://github.com/pydata/xarray/issues/3815

I think this works in the typical directory store.

Version and installation information

Please provide the following:

• Value of zarr.__version__: 2.4.0
• Value of numcodecs.__version__: 0.6.4
• Version of Python interpreter: 3.7
• Operating system (Linux/Windows/Mac): linux
• How Zarr was installed (e.g., “using pip into virtual environment”, or “using conda”): conda, conda-forge

Also, if you think it might be relevant, please provide the output from pip freeze or conda env export depending on which was used to install Zarr.

[jakirkham]

Guessing that is referring to PR ( https://github.com/zarr-developers/zarr-python/pull/813 ) in Zarr 2.9.4+

[joshmoore]

Recent work by @abergou may have improved the situation with object codecs.