README.Debian: www.exim.org/bugzilla/show_bug.cgi?id=92 -> bugs.exim.org/show_bug.cgi?id=92

[Regid Ichira]

Hello,
/usr/share/doc/exim4-base/README.Debian.gz has a reference to
http://www.exim.org/bugzilla/show_bug.cgi?id=92 . URL has changed.
New URL is https://bugs.exim.org/show_bug.cgi?id=92 .
Should I file a bug about it at bugs.debian.org, or is this post sufficient?