Add bashi to blink/renderer/core/workers owner

To have more reviewers in the directory.

Bug: N/A
Change-Id: If6ed70615faeec47547660ebbc75ed5ebd06a425
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2437574Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Commit-Queue: Kenichi Ishibashi <bashi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811546}

third_party/blink/renderer/core/workers/OWNERS

+bashi@chromium.org
 falken@chromium.org
 hiroshige@chromium.org
 japhet@chromium.org