Can’t tell if CLI will use mamba

[jab]

Checklist

• [X] I added a descriptive title
• [X] I searched open reports and couldn't find a duplicate

What happened?

I ran ‘conda-lock lock --help’ to see what the default value of the --mamba flag would be in the current environment, but the default value was not shown.

Fixing this should just be a matter of passing show_default=True to the click.option call (or enabling that for all options).

Conda Info

N/A

Conda Config

N/A

Conda list

N/A

Additional Context

Thanks for maintaining conda-lock!