Update Authority

Description:

Set or update a permission on an account.

The [authority] field can be either a *public key* or a path to a YAML
file.

If you specify a public key, a simple 'authority' structure is built,
with a threshold of 1, and a single key.

Otherwise, it should be a path to a YAML file.  Here is a sample YAML
authority file:

---
threshold: 3
keys:
- key: EOS6MRyAjQq8ud7hVNYcfn................tHuGYqET5GDW5CV
  weight: 1
accounts:
- permission:
    actor: accountname
    permission: namedperm
  weight: 1
waits:
- wait_sec: 300
  weight: 1
---

Usage:

eosc system updateauth [account] [permission_name] [parent permission or ""] [authority] [flags]