Support for SecKeychainAddInternetPassword

[peterj]

Summary

The package currently calls SecKeychainAddGenericPassword to store the items in the keychain on macOS. Are there any plans to support the SecKeychainAddInternetPassword as well?

This also means if you have items of type 'internet password' in the keychain, you can't use keytar to retrieve them.

Motivation

I am using keytar to store credentials for Docker registries - using keytar, a generic password entry gets created. Docker CLI has the ability to automatically read the credentials from the keychain, without prompting the user for username/password. However, it can't use the generic password types - the entry needs to be of an internet password type.

In addition to the Docker CLI scenario, this change will also allow retrieving 'internet password' items from the keychain.