Update plugin com.diffplug.spotless to v8

Author: renovate[bot]

build.gradle

@@ -20,7 +20,7 @@ import net.ltgt.gradle.errorprone.CheckSeverity
 import java.text.SimpleDateFormat
 
 plugins {
-  id 'com.diffplug.spotless' version '6.10.0'
+  id 'com.diffplug.spotless' version '8.1.0'
   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'