document method=https, and use it in the example config;

from lauri tirkkonen;
ok sthen beck

src/etc/mail/spamd.conf

@@ -1,4 +1,4 @@
-# $OpenBSD: spamd.conf,v 1.8 2016/06/01 21:55:47 sthen Exp $
+# $OpenBSD: spamd.conf,v 1.9 2018/07/22 17:09:43 jmc Exp $
 #
 # spamd(8) configuration file, read by spamd-setup(8).
 # See also spamd.conf(5).
@@ -27,7 +27,7 @@ nixspam:\
 	:black:\
 	:msg="Your address %A is in the nixspam list\n\
 	See http://www.heise.de/ix/nixspam/dnsbl_en/ for details":\
-	:method=http:\
+	:method=https:\
 	:file=www.openbsd.org/spamd/nixspam.gz
 
 # An example of a list containing addresses which should not talk to spamd.