Adding yaml-cpp in fboss oss build
Adding yaml-cpp in fboss oss build

Summary: The new library firmware_storage needs the yaml-cpp. For OSS build this diff adds the yaml-cpp library to manifest

Reviewed By: shri-khare

Differential Revision: D25115387

fbshipit-source-id: 9ed1c374df7e87f284c48d366095a20183719534

facebook/folly,facebook/folly,facebook/folly,facebook/folly,facebook/folly