folder('project-a') {
    displayName('Folder A')
    description('Folder for project A')
    properties {
        folderLibraries {
            libraries {
                libraryConfiguration {
                    name("my-lib")
                    retriever {
                        modernSCM {
                            scm {
                                git {                        
                                        remote("https://somebitbucket.com/scm/project/reponame.git")
                                        credentialsId("jenkins-bitbucket")
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}