Default to strong dkim.

Author: jnorell

install/tpl/server.ini.master

@@ -37,7 +37,7 @@ maildir_path=/var/vmail/[domain]/[localpart]
 homedir_path=/var/vmail
 maildir_format=maildir
 dkim_path=/var/lib/amavis/dkim
-dkim_strength=1024
+dkim_strength=4096
 content_filter=amavis
 rspamd_password=
 pop3_imap_daemon=courier