updated maven pom to use repo.jenkins-ci.org repository
updated maven pom to use repo.jenkins-ci.org repository

vjuranek/ws-cleanup,jenkinsci/ws-cleanup-plugin,jalios/ws-cleanup-plugin,jalios/ws-cleanup-plugin,KostyaSha/ws-cleanup-plugin,vjuranek/ws-cleanup,jenkinsci/ws-cleanup-plugin,KostyaSha/ws-cleanup-plugin