Fixed issue #287 of login.webmaker.org at Github

Broken Link under the Bugs Section of README.md. The original link https://bugzilla.mozilla.org/buglist.cgi?quicksearch=c%3Dlogin&list_id=6396195 (text: bugs we have now) was broken, needed to be fixed.
Can you remove the `&list_id=8483855` part from this URL? r+ with that change