Support for Triple-T Gradle Publisher 2.0 metadata directory structure

The Triple-T Gradle Play Publisher directory structure has changed in the latest version of the plugin. Many users are expected to migrate very soon as the previous version seems to have stopped working with Google Play.

F-Droid doesn't seem to be pulling any metadata from my code repository since I migrated to the new structure.

Description of the new directory structure: https://github.com/Triple-T/gradle-play-publisher/blob/2.0.0-beta1/README.md#publishing-listings