[automerger skipped] audio: Update README.md to add info about the AIDL...

[automerger skipped] audio: Update README.md to add info about the AIDL version am: 5aca7616 -s ours am: 8b22eef8 -s ours am: f72d4a1a -s ours

am skip reason: Merged-In Ia627e3845a078e6a4c545b13a723a6c5a038c53b with SHA-1 6a9f697d is already in history

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2197315



Change-Id: Ib2ad3b383c67b71ae38d3b4fdd40c3fb4ae3d1f8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>