Add example for metadata

[dja]

I've tried formatting metadata every which way (when using the command line), and getting the error that it requires an object with key/value pairs. Instead of accepting the key/value pairs I'm sending it, it's seeing it as a string. Can you add examples of metadata formatting?

[dja]

It also looks like it only attempts to send metadata if specified as --metadata, which isn't in the documentation.

[abigailbramble]

Hi @dja thanks for the report! It looks like there is a bug where metadata cannot be specified when using the CLI. We will look into getting this fixed.