Update plugin com.diffplug.spotless to v7

Author: renovate[bot]

build.gradle.kts

@@ -7,7 +7,7 @@ plugins {
     `maven-publish`
     signing
 
-    id("com.diffplug.spotless") version "6.25.0"
+    id("com.diffplug.spotless") version "7.0.2"
     id("io.github.gradle-nexus.publish-plugin") version "2.0.0"
 
     idea