[swarming] add OWNERS
[swarming] add OWNERS

Can I have additional OWNERS for swarming recipe_module?

Change-Id: Ic30a23b8b9aeb0a425d430e9fbc8ae95647e4d32
Reviewed-on: https://chromium-review.googlesource.com/c/1416493
Commit-Queue: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Reviewed-by: Robbie Iannucci <40f3d43a28ebae3cb819288542e1c84d73d962d5@chromium.org>

luci/recipes-py,luci/recipes-py