AGP 3.x sample

[eirnym]

Android sample uses AGP 3.x is missing. Google releases updates for this branch, so it should be supported.

Beside sample code, I haven't found supported by AGP 3.x Gradle version range.

[hannesa2]

Who needs this ? Simply don't support AGP 3.x. Who needs it should put afford into this

[eirnym]

makes sense. AGP 4.x needs the same level of support, though :)