Add annotationProcessorPaths to the pom.xml code snippet

[mk868]

As of JDK23, javac doesn't automatically detect discoverable annotation processors by default.
In this PR, I add the explicit definition of the processor annotation in the maven-compiler-plugin.
I hope this will make it easier for future users to add RecordBuilder to their project.

Sources:

• Changes Default Annotation Processing Policy

Edit
Worth to add: for Gradle, the annotation processor is already explicitly defined via annotationProcessor, so there is no problem with JDK23.

[Randgalt]

Thank you.