Bump com.diffplug.spotless from 6.9.0 to 6.9.1 (#292)

Author: dependabot[bot]

build.gradle

@@ -6,7 +6,7 @@ plugins {
 	id 'signing'
 	id 'pmd' //code check, working on source code
 	id 'com.github.spotbugs' version '5.0.9' //code check, working on byte code
-	id 'com.diffplug.spotless' version '6.9.0'//code format
+	id 'com.diffplug.spotless' version '6.9.1'//code format
 	id 'jacoco' // java code coverage plugin
 	id "org.sonarqube" version "3.4.0.2513" // sonarqube
 	id "org.scoverage" version "7.0.0" // scala code coverage scoverage