Bind this checkout to a CircleCI project

## Usage

`circleci project link [flags]`

## Flags

| Flag                                     | Description                                                     |
| ---------------------------------------- | --------------------------------------------------------------- |
| `-f, --force`                            | Overwrite an existing .circleci/info.yml                        |
| `--project circleci/<orgID>/<projectID>` | Project slug (e.g. gh/org/repo or circleci/<orgID>/<projectID>) |

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

## Examples

- Auto-detect from the current git repository: 
  `circleci project link`
- Bind to a specific project (skips lookup if it exists): 
  `circleci project link --project gh/myorg/myrepo`
- Bind to a standalone project by its CircleCI slug: 
  `circleci project link --project circleci/<orgID>/<projectID>`
- Overwrite an existing .circleci/info.yml: 
  `circleci project link --force`

## Details

Record the CircleCI project for the current checkout in .circleci/info.yml, so
other commands resolve it without re-detecting from the git remote each time.

The project comes from `--project`, else the git remote (origin), else an
interactive prompt. Because the slug is verified against the CircleCI API,
this exits with an authentication error when you are not logged in rather
than prompting blindly.

