Pipeline that builds a maven project and tags the git repo

gistfile1.txt

pipeline {
    agent {
        docker {
            label 'docker'
            // Image containing java 8, maven 3.5.2 and git
            image 'legolas/maven:3.5.2-jdk-8-alpine'
            args '-v /root/.m2:/root/.m2'
        }
    }
    environment {
        VERSION_TAG='5.1.${BUILD_NUMBER}'
        // TODO this needs to be retrieved from the ${REPOSITORY_URL} with the prefix 'https://' stripped off.
        REPOSITORY_URL='repository.url/xxx/xxx/xxx.git'
    }

    stages {
        stage('Validate pom') {
            steps {
                sh 'mvn -B validate'
            }
        }

        stage('Set version') {
            steps {
                sh 'mvn -B versions:set -DnewVersion=${VERSION_TAG}'
            }
        }

        stage('Tag the version') {
            steps {
                withCredentials([usernamePassword(credentialsId: 'my-credentials', passwordVariable: 'GIT_PASSWORD', usernameVariable: 'GIT_USERNAME')]) {
                    sh "git tag ${VERSION_TAG}"
                    sh "git push https://${GIT_USERNAME}:${GIT_PASSWORD}@${REPOSITORY_URL} ${VERSION_TAG}"
                }
            }
        }
    }
}