Hello,

I'm trying to build with the latest Gradle (it would be handy to have somewhere in the README a mention of the version used to build the library) and I get an error in building

* What went wrong:
A problem occurred evaluating project ':richtextfx'.
> Could not set unknown property 'classifier' for task ':richtextfx:javadocJar' of type org.gradle.api.tasks.bundling.Jar.

From quickly looking, it seems that it is simply due to deprecated "classifier" used in the build:
It seems that instead

jar {
    classifier = 'sources'
}

For version 8+ you should use:

jar {
    archiveClassifier.set('sources')
}