another way of getting the branch name

Signed-off-by: Andrew Berezovskyi <andriib@kth.se>

Jenkinsfile

@@ -4,11 +4,22 @@ pipeline {
 		maven 'apache-maven-latest'
 		jdk 'temurin-jdk11-latest'
 	}
+	pipeline {
+		environment {
+			// https://stackoverflow.com/questions/42383273/get-git-branch-name-in-jenkins-pipeline-jenkinsfile
+			BRANCH_NAME_B = "${GIT_BRANCH.split("/")[1]}"
+			BRANCH_NAME_A = "${GIT_BRANCH.split("/").size() > 1 ? GIT_BRANCH.split("/")[1] : GIT_BRANCH}"
+			BRANCH_NAME = "${GIT_BRANCH.split('/').size() > 1 ? GIT_BRANCH.split('/')[1..-1].join('/') : GIT_BRANCH}"
+		}
+	}
 	stages {
 		stage('Debug') {
 			steps {
 				script {
 					echo 'Working on' + env.BRANCH_NAME
+					echo '... or A' + env.BRANCH_NAME_A
+					echo '... or B' + env.BRANCH_NAME_B
+					echo 'CHANGE_BRANCH' + env.CHANGE_BRANCH
 				}
 			}
 		}