Added support for Keychain Access Flags which are available since iOS 12, for added security.

I needed the Access control flag to set .biometricCurrentSet as per security guidelines that prevents Keychain Bypass vulnerability. Reference the following document:

https://github.com/sensepost/objection/wiki/Understanding-the-iOS-Biometrics-Bypass

You can ignoring merging it to main branch. Just sharing it so if others find it helpful, they can use this fork directly. Kudos for making the wrapper super user friendly.