Treat `spago --version` the same as `spago version`

[hdgarrood]

Almost all of the other CLI tools I use regularly recognise --version, and I find myself writing spago --version quite often:

$ spago --version
Invalid option `--version'

Did you mean this?
    version

It would be nice if spago version and spago --version were treated the same way.

[f-f]

Yeah, this sounds good to me 👍