No way to update/upgrade installed API specs #17

Trying to: Update an installed API to get the latest OpenAPI spec

Tried:

clx upgrade stripe
clx update stripe

Got:

error: unknown command 'upgrade'
error: unknown command 'update'

Expected: A command like clx upgrade <api> or clx update <api> to refresh the OpenAPI spec from the registry.

Impact: Users have to remove and install to get updates. No way to know if updates are available.