Add HS Code info to InventoryItem

[c9845]

The InventoryItem type is missing a number of fields to handle HS code information. Specifically, country_code_of_origin, country_harmonized_system_codes, harmonized_system_code, and province_code_of_origin.

Not sure if these were omitted for a specific reason or added to Shopify's API after this package was built out. Can these be added?

See https://shopify.dev/docs/api/admin-rest/2023-04/resources/inventoryitem#resource-object for the list of fields available for an InventoryItem.

[oliver006]

Thanks for raising this. they were not omitted for a specific reason, probably cause they just got added later or the original author didn't need them.

This definitely could use some help, open a PR if you have a minute and I'll review and merge it asap.

[oliver006]

I think this got addressed by #213