in buildSrc/src/main/groovy/HttpUtil.groovy [32:38]
static HttpRequest headRequest(url, user, password) {
HttpRequest.newBuilder()
.uri(new URI(url))
.header('Authorization', 'Basic ' + "$user:$password".getBytes('iso-8859-1').encodeBase64())
.method("HEAD", HttpRequest.BodyPublishers.noBody())
.build()
}