Update dependency com.diffplug.spotless:spotless-plugin-gradle to v6.4.2

Signed-off-by: Renovate Bot <bot@renovateapp.com>

build.gradle

@@ -21,7 +21,7 @@ buildscript {
     dependencies {
         classpath 'com.adarshr:gradle-test-logger-plugin:3.2.0'
         classpath 'gradle.plugin.com.github.johnrengelman:shadow:7.1.2'
-        classpath 'com.diffplug.spotless:spotless-plugin-gradle:6.4.1'
+        classpath 'com.diffplug.spotless:spotless-plugin-gradle:6.4.2'
     }
 }