[memory] Add ambre and nathaniel to memory OWNERS

Change-Id: If9b06b4688b19d0720c6ef8120098a2ec7c05e1f
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1550402
Commit-Queue: Étienne J. Membrives <etiennej@google.com>
Reviewed-by: Nathaniel Manista <nathaniel@google.com>
1 file changed