This resolves#5523
While bumping `com.android.tools.build:gradle:3.1.2` to `3.3.0`, some other plugins/artifacts/maven repo/buildscripts have to be updated:
- gradle (wrapper) need to upgrade to 4.10.x
- protobuf gradle plugin need to bump a version compatible with gradle version.
- need add `google()` and `jcenter()` repos for android (otherwise `com.android.tools.build:aapt2:3.3.0x` and `trove4j` will not be found resp.)
- need to accept license for Android "build-tools;28.0.3" in kokoro env.
This opens up the ability of dependency locking and the now-stable Maven
Publish Plugin. Also failOnVersionConflict no longer needs to be
commented out for the dependency insight report.
The examples are no longer part of the normal build, although they are
built with Travis. The examples now include their own copy of the gradle
wrapper to ease usage from IDEs which can now properly detect the
correct version of gradle to use.
The build files were generated using "gradle init" and "mvn
archetype:generate" and then modified following our README.
Fixes#1414
ZHANG Dapeng
Eric Anderson
Eric Gribkoff
Carl Mastrangelo