[Files App] Add jboulic to OWNERS

BUG=None

Change-Id: Icfe308b3d0c40f82884ed8f658a4ec7ab191dbb7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2220406Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: François Degros <fdegros@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772995}

ui/file_manager/OWNERS

@@ -4,6 +4,7 @@ austinct@chromium.org
 dats@chromium.org
 fdegros@chromium.org
 fukino@chromium.org
+jboulic@chromium.org
 joelhockey@chromium.org
 lucmult@chromium.org
 noel@chromium.org