--format= option for CLI list command

[sammck]

It would be nice to have a way to dump all variables as JSON, which can be used by many other tools. I'd propose addition of a --json or -j option on the "list" command.

I'd be happy to submit a pull request if it sounds interesting.

[theskumar]

I like the idea. Looking forward a pull-request. Thanks Also, how about adding the option as "--format=json" which then allows for extending to other formats.

[sammck]

sorry i missed your format= suggestion; I will revise and resubmit

[sammck]

I was inspired by your idea to allow more formats with "--format=", and I added two more formats, "shell" and "export". These formats can be directly executed by a posix shell, as in:

eval "$(dotenv list --format=shell)"

[theskumar]

Nice I'll review it over the weekend!