[iOS] support expirationHandler

[petergaultney]

This is just a feature request, but it would be very helpful to me if this library supported passing a JS callback for the iOS-only expiration handler that allows you to 'clean up' for 1 second before your task is ended.

https://developer.apple.com/documentation/uikit/uiapplication/1623031-beginbackgroundtask

I am essentially incompetent as an Objective C developer, or I'd happily contribute a PR. :P

[Rapsssito]

@petergaultney thanks for the feedback! I will take a look at it and come back to you as soon as I get something.

[github-actions]

🎉 This issue has been resolved in version 2.6.0 🎉

The release is available on:

• GitHub release
• npm package (@latest dist-tag)

Your semantic-release bot 📦🚀