[automerger skipped] Add mainline extension and METADATA.txt to boot.zip. am:...

[automerger skipped] Add mainline extension and METADATA.txt to boot.zip. am: dac9d66a am: 0f096fd3 -s ours

am skip reason: Merged-In I258479ffbdf199091290b074329ff1b43db2e669 with SHA-1 a5551c5d is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/+/23658853



Change-Id: I0f50a86d939985d3342ecd7f798842d4ba9f53e6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>