CLI deployments subcommand

[jlewi]

It would be nice to have a CLI subcommand for the CRUD operations associated with deployments.
This would make be useful for CICD.
https://replicate.com/docs/reference/http#deployments.update

[mattt]

@jlewi Great idea! I pushed a draft PR with most of that here: #95

Still need to implement update and delete, but list, show, schema, and create are working.