If you were looking for solution to send a Push Notifications using Auth Key (P8), this repository may interest you.
Special thanks to @ethanhuang13 and his https://github.com/ethanhuang13/CupertinoJWT which is heavily used in this project. Thanks!
Just download P8.playground
file and open it in Xcode.
Change the following data in playground and run it.
PAYLOAD // content of push notification
DEVICE_TOKEN // device token to which the notification should be sent
KEY_ID // get it from your developer account
TEAM_ID // get it from your developer account
BUNDLE_ID // your app bundle id
P8 // generated private key
The project is available as open source under the terms of the MIT License.