use new workflow build script

[stokito]

all other plugins use the build.yml. Not sure if it better or worth

[stokito]

ok, it doesn't work "Could not locate plugin.xml"

[GregDThomas]

I probably wouldn't spend too much time on this plugin on right now
a) The plugin was designed to be built with Gradle, rather than Maven, partly as on experiment, partly to make development easy (e.g. gradlew deploy will deploy the plugin to the currently running Openfire, hard to do - at least for me - with Maven)
b) The plugin doesn't work with the current version of Openfire anyway - some core APIs changed and it needs a few updates.

[stokito]

yeah, I hope that someone who will find the functionality useful will send a PR to resolve the issues