OWNERS.toolchain: clean up

The CrOS toolchain team has seen changes over the last ~year and a half.
This CL updates this file to match the current toolchain team.

BUG=None
TEST=None

Change-Id: I65e08922bb91fd5634e30c1e717fe28e62c68ce6
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/3133551
Reviewed-by: Ryan Beltran <ryanbeltran@chromium.org>
Reviewed-by: Christopher Di Bella <cjdb@google.com>
Reviewed-by: Jordan R Abrahams <ajordanr@google.com>
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: Michael Benfield <mbenfield@google.com>
Commit-Queue: George Burgess <gbiv@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>
1 file changed