fix(release): make sure we are not on a detached branch else semantic…

… release has issues (#159)

Jenkinsfile

@@ -5,16 +5,18 @@ def org = 'fabric8-ui'
 def repo = 'ngx-fabric8-wit'
 fabric8UINode{
     ws {
-      git "https://github.com/${org}/${repo}.git"
+      checkout scm
       readTrusted 'release.groovy'
-      sh "git remote set-url origin [email protected]:${org}/${repo}.git"
       def pipeline = load 'release.groovy'
 
       if (utils.isCI()){
         container('ui'){
           pipeline.ci()
         }
       } else if (utils.isCD()){
+        sh "git checkout master"
+        sh "git pull"
+        sh "git remote set-url origin [email protected]:${org}/${repo}.git"
         def branch
         container('ui'){
             branch = utils.getBranch()