https://github.com/jenkinsci/job-dsl-plugin/wiki/Testing-DSL-Scripts and other locations/scripts contain deprecated invocations and old versions.

For example even 6.x gradle will complain about using testCompile Et Al. and the provided }}{{JobScriptsSpec.groovy{{ won't work with Spock 2.0 (which is needed to support groovy 3).}}

Could you please take a look and upgrade those?{{}}