Using with Grails 5.2.x -- repo location? #18

Hello,
I am trying to use the taggable plugin on a 5.2.4 grails app. It looks like this github repo has been updated somewhat recently, but some of the content might be out of sync? Or, I may be missing some obvious things...

The docs say to add
compile "io.github.gpc:taggable:4.0.0"
to the dependencies, but AFAIU that is outdated in recent gradle, and perhaps should be
implementation "io.github.gpc:taggable:4.0.0"
?

Also, the docs seem to suggest the plugin is available in the standard grails plugin site. I can no longer find it there, and get an error suggesting that the 'stanard' repos don't know about it.

buildscript {
    repositories {
        maven { url "https://plugins.gradle.org/m2/" }
        maven { url "https://repo.grails.org/grails/core" }
    }

Any pointers to overcome my misunderstandings would be most welcome :-)