Support sharing keychain items using App Groups

[dfed]

Currently, we only support sharing keychain items with Keychain Access Groups.

We should also support keychain sharing via App Groups.

More information on the differences between Keychain Access Groups and App Groups can be found in Apple's documentation.

[dfed]

Worth noting that the format of App Group IDs differ on macOS and other platforms.

[dfed]

According to the documentation on kSecAttrAccessGroup, it seems that App Group sharing uses the kSecAttrAccessGroup key. Which means that we may have enabled unofficial support for App Groups in #218 when we enabled explicitly setting the access group prefix. If I'm right, supporting this feature may be as simple as updating the docs and tests. Investigating.

[dfed]

An initial investigation reveals that we are indeed supporting this functionality today! I'm working on a PR to update some names to make the support a bit more semantic. PR incoming. We'll want to land this in Valet 4 (or roll a Valet 5 fast-follow, which seems less-than-ideal).

[NickEntin]

Awesome! Landing in Valet 4 sounds good. 👍

[dfed]

This will be released in Valet 4. Closing this issue.