[skip ci] Add comment for get author email (#13478)

Signed-off-by: Jenny Li <jing.li@zilliz.com>

tests/scripts/get_author_email.sh

@@ -1,5 +1,6 @@
 #!/bin/bash
 # author emaill will be jenkins's email, when the pr branch is not fast forward compared with master branch
+# Exit immediately for non zero status
 set -e
 function get_author_email(){
     email=$(git --no-pager show -s --format=\'%ae\' HEAD )