Update pipeline to pass variable to downstream job

Update piplines to allow CI_SCRIPTS_BRANCH variable to be used in
downstream jobs.

Fix: Update build pipelines to checkout code rather than using the git
plugin. This is due to a bug in the Jenkins git plugin that does not
fetch tags.

Signed-off-by: Colin Thorbinson <colin.thorbinson@arm.com>
Change-Id: I902496b0a96129fa25557e2051330cda8f4a0fd1
diff --git a/jenkins/build-docs.jpl b/jenkins/build-docs.jpl
index 559f94d..e63ab73 100644
--- a/jenkins/build-docs.jpl
+++ b/jenkins/build-docs.jpl
@@ -26,7 +26,7 @@
         ])
     }
     dir("tf-m-ci-scripts") {
-      git url: '$CI_SCRIPTS_REPO', branch: '$CI_SCRIPTS_BRANCH', credentialsId: 'GIT_SSH_KEY'
+      checkout([$class: 'GitSCM', branches: [[name: '$CI_SCRIPTS_BRANCH']], userRemoteConfigs: [[credentialsId: 'GIT_SSH_KEY', url: '$CI_SCRIPTS_REPO']]])
     }
     dir("mbedtls") {
       checkout(