[monitoring-plugins] check_smtp: add missing -r option in usage

[Franz Schwartau]

 Module: monitoring-plugins
 Branch: master
 Commit: 6d5e81fcbadbef557cf3f61ce7fd6ef73e25683e
 Author: Franz Schwartau <franz at electromail.org>
   Date: Mon Jun 12 15:55:32 2023 +0200
    URL: https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=6d5e81f

check_smtp: add missing -r option in usage

---

 plugins/check_smtp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/plugins/check_smtp.c b/plugins/check_smtp.c
index addabfc..a1debd2 100644
--- a/plugins/check_smtp.c
+++ b/plugins/check_smtp.c
@@ -875,6 +875,6 @@ print_usage (void)
   printf ("%s\n", _("Usage:"));
   printf ("%s -H host [-p port] [-4|-6] [-e expect] [-C command] [-R response] [-f from addr]\n", progname);
   printf ("[-A authtype -U authuser -P authpass] [-w warn] [-c crit] [-t timeout] [-q]\n");
-  printf ("[-F fqdn] [-S] [-L] [-D warn days cert expire[,crit days cert expire]] [-v] \n");
+  printf ("[-F fqdn] [-S] [-L] [-D warn days cert expire[,crit days cert expire]] [-r] [-v] \n");
 }