Show cobra errors

[divolgin]

Before:

$ ./bin/replicated customer update 

Usage:
  replicated customer update --customer <id> --name <name> [options] [flags]
...

After:

$ ./bin/replicated customer update 
Error: required flag(s) "channel", "customer", "name" not set

Usage:
  replicated customer update --customer <id> --name <name> [options] [flags]
...