Add BoringSSL maintainer to OWNERS. am: 2314508561

Original change: https://android-review.googlesource.com/c/platform/external/boringssl/+/2477675

Change-Id: Id6049633b045f186d4e71713dcd0ab5247aa5bfc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>