fix: update comments for scripts

Signed-off-by: Junjie Gao <[email protected]>

test/e2e/scripts/gen_crl_testing_certs.sh

@@ -20,6 +20,10 @@
 # - leaf.key: the private key of the leaf certificate.
 # - leaf_revoked.crl: the CRL file that includes the revoked leaf certificate.
 # - root.crt: the root certificate.
+#
+# Note: The script will not run in the pipeline, but we need to keep it for
+# future maintenance because generating those test certificates with CRL is not
+# easy.
 
 # Create root CA configuration file
 cat > root.cnf <<EOF