Use custom build command for JitPack

Default command was:
 ./gradlew clean -Pgroup=XXX -Pversion=YYY -xtest -xlint assemble publishToMavenLocal

But that assemble task is building also debug variants unnecessarily, risking timeouts and failed builds.

We can replace it with assembleRelease, or we can simply call just:
 ./gradlew clean -xtest -xlint publishToMavenLocal

Release version 4.8.0

Release version 4.7.0

Release version 4.6.0

Fix JitPack build (again)

Release version 4.4.0

Release version 4.3.0

Release version 4.2.0

Fix building on JitPack

They doesn't have latest CMake installed by default.
But to install it, we need to use sdkmanager which
doesn't support Java 11. So we must first use Java 8,
download cmake, then install and use Java 11.

Alternatively we can forget about installing newer CMake
as compilation works also with older version, but there
are warnings that NDK needs newer CMake. And we would also
have to remove the required CMake version from build.gradle.

Also we must ignore :sample project when building on JitPack
as it breaks build too.

Release version 4.1.1

This release has no real changes compared to 4.1.0. It just fixes compiling on JitPack.