Generate a runner agent configuration file

## Usage

`circleci runner config <resource-class> [flags]`

## Arguments

`<resource-class>` is the runner resource class to generate config for,
in the form `namespace/name` (for example, `my-org/my-runner`).

## Flags

| Flag                  | Description                                               |
| --------------------- | --------------------------------------------------------- |
| `--nickname string`   | Nickname for the new token                                |
| `-o, --output string` | Write config to this file instead of stdout               |
| `--token string`      | Use an existing token value instead of creating a new one |

Global flags: `-c, --config`, `--debug`, `--no-color`, `-q, --quiet` — see `circleci --help`.

## Examples

- Create a new token and print config to stdout: 
  `circleci runner config my-org/my-runner`
- Write config directly to a file: 
  `circleci runner config my-org/my-runner --output circleci-runner-config.yaml`
- Create a nicely-labeled token and write to a file: 
  `circleci runner config my-org/my-runner --nickname "prod-server-1" --output /etc/circleci-runner/circleci-runner-config.yaml`
- Generate config from an existing token value (no API token creation): 
  `circleci runner config my-org/my-runner --token "$EXISTING_TOKEN_VALUE"`

## Details

Generate a runner agent configuration YAML for a resource class, suitable for
use as the agent's circleci-runner-config.yaml.

A new authentication token is created unless you pass an existing one with
--token, which generates the YAML without an API call.

