fix: add mail template

  function prepare_mail_template() {

    log_info "prepare mail template"

    cat > /tmp/mail.txt <<-EOF

    	To: $GITLAB_USER_EMAIL

    	From: notif@defectdojo

    	Subject: New vulnerabilities in $CI_PROJECT_PATH

    	Hello,

    	DefectDojo found <<nb>> new $DEFECTDOJO_NOTIFICATION_SEVERITIES vulnerabilities in $CI_PROJECT_PATH.

    	EOF

  }

  function import_into_defectdojo() {