[Enhancement] Check Message-ID RHS against popular DNSBLs by default

conf/modules.d/rbl.conf

@@ -205,7 +205,7 @@ rbl {
     "SURBL_MULTI" {
       ignore_defaults = true;
       rbl = "multi.surbl.org";
-      checks = ['emails', 'dkim', 'helo', 'rdns', 'replyto', 'urls'];
+      checks = ['emails', 'dkim', 'helo', 'rdns', 'replyto', 'mid', 'urls'];
       emails_domainonly = true;
       exclude_users = false;
 
@@ -241,7 +241,7 @@ rbl {
     "URIBL_MULTI" {
       ignore_defaults = true;
       rbl = "multi.uribl.com";
-      checks = ['emails', 'dkim', 'helo', 'rdns', 'replyto', 'urls'];
+      checks = ['emails', 'dkim', 'helo', 'rdns', 'replyto', 'mid', 'urls'];
       emails_domainonly = true;
       exclude_users = false;
 
@@ -274,7 +274,7 @@ rbl {
       ignore_defaults = true;
       rbl = "dbl.spamhaus.org";
       no_ip = true;
-      checks = ['emails', 'dkim', 'helo', 'rdns', 'replyto', 'urls'];
+      checks = ['emails', 'dkim', 'helo', 'rdns', 'replyto', 'mid', 'urls'];
       emails_domainonly = true;
       exclude_users = false;