Gernerating Dart model class from Json file.
#wbt update：
- update dependencies lastest version.
- convert filename to classname, use camel-cast name。
dev_dependencies:
json_model:
git:
url: "https://github.com/wbtvc/json_model.git"
build_runner: ^1.6.0
json_serializable: ^3.0.0