Merge "Add py.typed file to export types to dependents." am: 4e13a43693 am: a79de22044

Original change: https://android-review.googlesource.com/c/platform/development/+/2363011

Change-Id: Ifdb6a67c73a29f491078ed9a00e937c287e9d331
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>