官方接口：
1、通过appId获取信息
https://itunes.apple.com/lookup?id=应用ID
2、通过应用名称获取信息
https://itunes.apple.com/search?term=你的应用程序名称&entity=software
demo：
AFN 3.0请求代码
AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
manager.responseSerializer.acceptableContentTypes = [NSSet setWithObjects:@"text/javascript", nil];
[manager POST:@"https://itunes.apple.com/lookup?id=284910350" parameters:nil progress:nil success:^(NSURLSessionDataTask * _Nonnull task, id _Nullable responseObject) {
NSLog(@"success:%@",responseObject);
} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
}];
