Use the newly provided backward-compatible aapt2 for builds

With G now providing aapt2.jar optimized for older isa, allowing for reproducible builds of apps built using current Gradle versions. It would make sense to update build scripts of the previously effected apps (not only the ones that protested against it) or even use this as a default.

From my side you can gladly update the neo apps again using the patched jars as long as this produce reproducible builds (not f-droid-internally-comparables, rather compared to the ones built from the original source code).