Add mailmap entry for Megan Batty

Author: tkremenek

.mailmap

@@ -103,6 +103,7 @@ Max Moiseev <moiseev@apple.com> <moiseev@users.noreply.github.com>
 Maxwell Swadling <maxs@apple.com> <maxwellswadling@gmail.com>
 Maxwell Swadling <maxs@apple.com> <mswadling@apple.com>
 Mayur Raiturkar <mayur@mayur.xyz> <mayurkr@users.noreply.github.com>
+Megan Batty <megan@stormbrew.ca> <graham.batty@apple.com>
 Michael Gottesman <mgottesman@apple.com> <gottesmm@users.noreply.github.com>
 Michael Ilseman <milseman@apple.com> <michael.ilseman@gmail.com>
 Mike Ash <mikeash@apple.com> <mike@mikeash.com>