RFE: Add to documentation how to push to docker registry V2

[Andrei-Stepanov]

Hello.
This is not a bug. Rather, ask to add add missing documentation.
At this moment the documentation say to use base64, and craft config.json. But. This approach works only for docker registry V1. This is really time consuming when you try all different variants of urls and protocols in config.json and --destination, but get all time the same error:

error checking push permissions -- make sure you entered the correct tag name, and that you are authenticated correctly, and try again: checking push permission for "docker-registry.company.com/osci/astepano_test:latest": creating push check transport for docker-registry.company.com failed: unsupported status code 401

1. Update the doc, and add to existing example, and say it applies only to V1.

2. Ridiculously, there is no example for how to push to V2. So, please add it.
   For V2, there is no need to use base64

{
    "auths": {
        "https://docker-registry.company.com/v2/": {
            "username": "ignore",
            "password": "token"
        }
    }
}

And add parameter example

--destination=docker-registry.company.com/namespace/image:tag