Update my name/email in .mailmap

Author: lilyball

.mailmap

@@ -175,6 +175,7 @@ Lennart Kudling <github@kudling.de>
 Léo Lanteri Thauvin <leseulartichaut@gmail.com>
 Léo Lanteri Thauvin <leseulartichaut@gmail.com> <38361244+LeSeulArtichaut@users.noreply.github.com>
 Léo Testard <leo.testard@gmail.com>
+Lily Ballard <lily@ballards.net> <kevin@sb.org>
 Lindsey Kuper <lindsey@composition.al> <lindsey@rockstargirl.org>
 Lindsey Kuper <lindsey@composition.al> <lkuper@mozilla.com>
 Luke Metz <luke.metz@students.olin.edu>