Merge "Add py.typed file to export types to dependents." am: 4e13a43693 am: a79de22044 am: 910896d0a4

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

Change-Id: I1193713bbf79c3d4155e96bd5f659bb7d9edd369
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>