Update bin/dwhich.dart?

Hey there @bsutton -- getting into all of this.

Could you confirm that dwhich.dart needs to be updated?

It seems to be still using an old Args class from an earlier version of DCLI (3.x.x?)

It also seems that the new ExitException in DCLI 4.x found here:
https://github.com/onepub-dev/dcli/blob/master/dcli_sdk/lib/src/util/exit.dart
or here:
https://github.com/onepub-dev/dcli/blob/master/dcli_sdk/lib/src/util/exceptions.dart

And perhaps a related class here:
https://github.com/onepub-dev/dcli/blob/master/dcli_core/lib/src/util/dcli_exception.dart
and here:
https://github.com/onepub-dev/dcli/blob/master/dcli_core/lib/src/util/run_exception.dart

Let me know if this is relevant/related, happy to get this updated with a bit of direction!

Cheers,
-Tsavo

从 bin/dwhich.dart 开始，将 Args 和异常的使用方式与 issue 中链接的 DCLI 4.x 文件进行比较：dcli_sdk/lib/src/util/exit.dart、dcli_sdk/lib/src/util/exceptions.dart、dcli_core/lib/src/util/dcli_exception.dart 和 dcli_core/lib/src/util/run_exception.dart。确认哪些 API 已经过时，并将完成标准定义为：dwhich.dart 已针对相关的 DCLI 4.x 接口完成更新。