[compiler] Update OWNERS

Add Nico, remove Ben and Jaro who left V8.

Change-Id: I6bee6f45e4933f286d8672114fdb5b89115172d2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2167439
Auto-Submit: Georg Neis <neis@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67392}

src/compiler/OWNERS

 bmeurer@chromium.org
-jarin@chromium.org
-titzer@chromium.org
 danno@chromium.org
 sigurds@chromium.org
 tebbi@chromium.org
@@ -8,6 +6,7 @@ neis@chromium.org
 mvstanton@chromium.org
 mslekova@chromium.org
 jgruber@chromium.org
+nicohartmann@chromium.org
 
 per-file wasm-*=ahaas@chromium.org
 per-file wasm-*=bbudge@chromium.org