Update getting-started.md (#61)
Update getting-started.md (#61)

Summary:
Using debugImplementation instead of deprecated debugCompile
Closes https://github.com/facebook/Sonar/pull/61

Differential Revision: D8466425

Pulled By: passy

fbshipit-source-id: b3dd4185b307933c0781a798385a66ab128b43f2

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper