Modify Readme
Modify Readme

- include SDK 29 and build tools 29.0.2 as included components

Signed-off-by: Arka Prava Basu <0e0e290d5a2b238bbccbf6c8c9e776f285d392a8@gmail.com>

mingchen/docker-android-build-box,mingchen/docker-android-build-box,mingchen/docker-android-build-box