Merge pull request #1758 from kubernetes-client/dependabot/maven/com.diffplug.spotless-spotless-maven-plugin-2.12.1

Bump spotless-maven-plugin from 2.11.1 to 2.12.1

Author: k8s-ci-robot

pom.xml

@@ -422,7 +422,7 @@
       <plugin>
         <groupId>com.diffplug.spotless</groupId>
         <artifactId>spotless-maven-plugin</artifactId>
-        <version>2.11.1</version>
+        <version>2.12.1</version>
         <configuration>
           <formats>
             <!-- common settings -->