Enable spotless check

jenkinsci#175 intentionally disabled
spotless checking so that the parent pom update could be merged.
Enable spotless checking again.

Author: MarkEWaite

pom.xml

@@ -29,7 +29,7 @@
     <!-- https://www.jenkins.io/doc/developer/plugin-development/choosing-jenkins-baseline/ -->
     <jenkins.baseline>2.479</jenkins.baseline>
     <jenkins.version>${jenkins.baseline}.3</jenkins.version>
-    <spotless.check.skip>true</spotless.check.skip>
+    <spotless.check.skip>false</spotless.check.skip>
   </properties>
 
   <dependencyManagement>