[parser] Add leszeks to OWNERS

Change-Id: I6e30593a907605d970fdb6250b0020cddac94e37
Reviewed-on: https://chromium-review.googlesource.com/c/1261443Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56405}

src/parsing/OWNERS

@@ -2,6 +2,7 @@ set noparent
 
 adamk@chromium.org
 gsathya@chromium.org
+leszeks@chromium.org
 littledan@chromium.org
 marja@chromium.org
 neis@chromium.org