Android: Move off Java 8 onto the latest release that Github supports

What is the current behaviour and why should it be changed?

The Jamulus for Android build process currently requires Java 8 to run. As Java 8 is out of support (since March 2022), the build should move onto the current GA LTS version (Java 17).

Unfortunately, whilst Android SDK has moved forwards, as of March 2020 only JDK 11 was supported (released 2018). JDK 17 (September 2021) is not yet supported.

Describe possible approaches

• Stick with Java 8 until JDK 17 support arrives
• Move to JDK 11 to remain on a supported Java version

I'd suggest we move to JDK 11. It's likely to take some time for Google to move to 17 - there does not appear to be any roadmap published. They may choose to wait until the next LTS after 17 comes out to move onto 17, for example, which will be around 2024.

Note that this does not affect Jamulus itself, only the Android APK packaging.

Arose here, agreed by @ann0see here and @hoffie here.

Beginne damit, den Android-Buildprozess und die Konfiguration für das APK-Packaging zu finden. Prüfe anschließend, wo Java 8 erforderlich ist und welche JDK-Versionen das Android SDK unterstützt. Stelle den Packaging-Build auf JDK 11 um und verifiziere, dass das Android-APK weiterhin erfolgreich erstellt wird.