Use CocoaPods for the jcore-ios dependency

[jcesarmobile]

Since the JCore library is already distributed through CocoaPods, would be good if you could use the CocoaPods dependency instead of the jcore-ios.a file.
You can use the podspec tag in the plugin.xml for that more info

jcore-ios.a prevents Capacitor apps from building, changing to the CocoaPods dependency should fix that.