Update repository url in README
Update repository url in README

Use an https url so it is publicly accessible.
jonnyro/jenkins-backup-script,sue445/jenkins-backup-script,yonexyonex/jenkins-backup-script,sue445/jenkins-backup-script,orafapires/jenkins-backup-script,jonnyro/jenkins-backup-script,yonexyonex/jenkins-backup-script,orafapires/jenkins-backup-script