Usage documentation examples use obsolete net.ltgt.apt plugin for Gradle

[mjustin]

The Gradle documentation in the reference guide and project readme both instruct the reader to use the net.ltgt.apt plugin. However, this plugin has declared itself obsolete as of Gradle 5.2:

The goal of this plugin was to eventually no longer be needed, being superseded by built-in features.
This has become a reality with Gradle 5.2 and IntelliJ IDEA 2019.1. tl;dr: this plugin is obsolete, don't use it. If you're using Eclipse though, continue reading.
[...]
If you're using Eclipse, please migrate to the com.diffplug.eclipse.apt plugin, which is a (maintained) fork of net.ltgt.apt-eclipse.

In short, unless Eclipse is being used, you can use the built-in Gradle annotation processing functionality. If Eclipse is being used, it looks like the com.diffplug.eclipse.apt plugin should be used instead.

Therefore, the documentation should be updated to use the built-in Gradle annotation processor support, rather than the obsolete plugin.

[filiphr]

Thanks for pointing this out. We are going to update the documentation and readme for this.