Capacitor 8 support

[Fillsen]

Capacitor v8 has been released, but this plugin still depends on older Capacitor versions. When using Capacitor 8, iOS build fails with:
Compiling for iOS 14.0, but module 'Capacitor' has a minimum deployment target of iOS 15.0

[franmc01]

Hi @Fillsen, I've opened a PR (#155) that adds Capacitor 8 support and fixes the iOS build error. The PR updates all dependencies and raises the iOS deployment target to 15.0 as required by Capacitor 8.