Rekado v3.1

New
* Added: Support for Android Q.
* Added: Characters limit for serial checker's field.
* Added: Lower case serial numbers support.
* Updated: Payloads will be stored in application's folder (/Android/data/com.pavelrekun.rekado/files).
* Updated: Payloads added using Storage Access Framework now.

Payloads
* Updated: Hekate to 5.0.0.

Development
* Updated: Kotlin to 1.3.40.
* Updated: Coroutines to 1.2.2.
* Updated: OkHTTP to 4.0.0.
* Updated: Gradle to 5.5.