Update maven-compiler-plugin and fix bug on it to allow incremental compilation

[fabriciofx]

Let's update maven-compiler-plugin to 3.8.0 version and fix a bug in this plugin which doesn't allow incremental compilation that increase compile and running time. To fix both we need change pom.xml to:

<plugin>
  <artifactId>maven-compiler-plugin</artifactId>
  <version>3.8.0</version>
  <configuration>
    <source>1.8</source>
    <target>1.8</target>
    <useIncrementalCompilation>false</useIncrementalCompilation>
  </configuration>
</plugin>

Please, pay attention to <version> and <useIncrementalCompilation> tag.

[0crat]

@llorllale/z please, pay attention to this issue

[0crat]

@fabriciofx/z this project will fix the problem faster if you donate a few dollars to it; just click here and pay via Stripe, it's very fast, convenient and appreciated; thanks a lot!