Update opensmtpd stability tag to 1.27.4

Author: wodbot

.env

@@ -102,7 +102,7 @@ OPENSEARCH_ADMIN_PASSWORD=VERY%@bad123password
 ADMINER_TAG=5-5.0.2
 APACHE_TAG=2.4-4.17.2
 MEMCACHED_TAG=1-2.21.3
-OPENSMTPD_TAG=7-1.27.3
+OPENSMTPD_TAG=7-1.27.4
 RSYSLOG_TAG=latest
 WEBGRIND_TAG=1-1.44.4
 XHPROF_TAG=3.22.4