Try and set the branch name

I figured out that the updater wasn't working because Jenkins was always setting the branch name to HEAD

Jenkinsfile

@@ -1,5 +1,8 @@
 pipeline {
     agent any
+    environment {
+         BRANCH_NAME = "${GIT_BRANCH.split("/")[1]}"
+    }
     options {
         buildDiscarder logRotator(artifactDaysToKeepStr: '', artifactNumToKeepStr: '', daysToKeepStr: '', numToKeepStr: '5')
     }