Upgrade plugin for Grails 4

[ilPittiz]

It'd be really nice to have the plugin updated to work with Grails 4, thanks!

[glebremniov]

@ilPittiz

It'd be really nice to have the plugin updated to work with Grails 4, thanks!

I've tried this plugin with Grails 4.1.0.M1 and it works like a charm. I guess with other 4.x versions there’s the same behavior.