make sure to put #!/usr/bin/env groovy at the top of the Jenkinsfile

Former-commit-id: 5af0774e12ea9d10f3fe10b77336df22d748c7de

ci/jenkins/Jenkinsfile

+#!/usr/bin/env groovy
+
 String cron_timezone = "TZ=Asia/Shanghai"
 String cron_string = BRANCH_NAME == "master" ? "H 0 * * * " : ""
 cron_string =  BRANCH_NAME == "0.5.1" ? "H 1 * * * " : cron_string