Allowing setting plugins.txt during init

Hello, I saw the linkedin post https://www.linkedin.com/posts/activity-6664183702781853696-NHkV that said this project is ready for beta-testing so decided to give it a go. We have still lots of legacy builds on Jenkins we would like to migrate to Gitlab and this project seems very promising.
However in our current jenkins setup, we use the plugins.txt approach where we maintain all installed Jenkins plugins(and any other configuration) in source control. This helps bring up a sandboxed Jenkins environment very easily with docker for testing.
In order to use this project, we need to be able to pass the plugins.txt file to jenkinsfile-runner .
From https://github.com/jenkinsci/jenkinsfile-runner#cli-options: Jenkinsfile-runner already supports passing a plugins.txt file:

-p (--plugins) FILE         : plugins required to run pipeline. Either a
                               plugins.txt file or a /plugins installation

right now is hard-coded to "/app/jenkins_home/plugins/" in init command https://gitlab.com/gitlab-org/jfr-container-builder/-/blob/master/lib/jenkinsfile_runner/commands/init.rb#L42

it would be helpful to pass the -p value during init command. Note if the -p is set then Dockerfile should then have COPY instruction for plugins.txt just like it has for jenkins.war thanks