docs: android reqs (#102)
docs: android reqs (#102)

Signed-off-by: a8d7fdba914ec41ef6e5a65854a2b125ca0691d3@lyft.com

Description: android requirements in the building docs
Risk Level: low
envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile,envoyproxy/envoy-mobile