Update plugin com.jfrog.artifactory to v6

Author: renovate[bot]

build.gradle

@@ -23,7 +23,7 @@ plugins {
   id 'com.diffplug.spotless' version '6.10.0'
   id 'com.github.ben-manes.versions' version '0.42.0'
   id 'com.github.hierynomus.license' version '0.16.1-fix'
-  id 'com.jfrog.artifactory' version '4.28.3'
+  id 'com.jfrog.artifactory' version '6.0.3'
   id 'io.spring.dependency-management' version '1.0.11.RELEASE'
   id 'me.champeau.jmh' version '0.6.6' apply false
   id 'net.ltgt.errorprone' version '2.0.2'