[maven-release-plugin] prepare release groovy-1.18
[maven-release-plugin] prepare release groovy-1.18

vjuranek/groovy-plugin,daniel-beck/groovy-plugin,jenkinsci/groovy-plugin,daniel-beck/groovy-plugin,daniel-beck/groovy-plugin,jenkinsci/groovy-plugin,jenkinsci/groovy-plugin,vjuranek/groovy-plugin