Disable plugin upgrade messages in Grails

_Events.groovy

//... Disable annoying plugin upgrade messages
def resolveDependenciesWasInteractive = false
eventResolveDependenciesStart = {
    resolveDependenciesWasInteractive = isInteractive
    isInteractive = false
}

eventResolveDependenciesEnd = {
    isInteractive = resolveDependenciesWasInteractive
}