Make futures-macro available to product and vendor am: d7d8eb6f83 am: 493c8b721a am: e8eb2ffaac am: df42857701

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/futures-macro/+/2475615

Change-Id: Ia0d2531b9fab63080cf2111d462fd454eeeb8a3f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>