async config(fileName, defaultConfig, deepMergeOptions) {
        const params = this.repo({
            path: path_1$3.default.posix.join(".github", fileName),
            defaults(configs) {
                const result = deepmerge_1.default.all([defaultConfig || {}, ...configs], deepMergeOptions);
                return result;
            },
        });
        // @ts-ignore
        const { config, files } = await this.octokit.config.get(params);
        // if no default config is set, and no config files are found, return null
        if (!defaultConfig && !files.find((file) => file.config !== null)) {
            return null;
        }
        return config;
    }
Reads the app configuration from the given YAML file in the `.github`
directory of the repository.

For example, given a file named `.github/config.yml`:

```yml
close: true
comment: Check the specs on the rotary girder.
```

Your app can read that file from the target repository:

```js
// Load config from .github/config.yml in the repository
const config = await context.config('config.yml')

if (config.close) {
  context.octokit.issues.comment(context.issue({body: config.comment}))
  context.octokit.issues.edit(context.issue({state: 'closed'}))
}
```

You can also use a `defaultConfig` object:

```js
// Load config from .github/config.yml in the repository and combine with default config
const config = await context.config('config.yml', {comment: 'Make sure to check all the specs.'})

if (config.close) {
  context.octokit.issues.comment(context.issue({body: config.comment}));
  context.octokit.issues.edit(context.issue({state: 'closed'}))
}
```

Config files can also specify a base that they extend. `deepMergeOptions` can be used
to configure how the target config, extended base, and default configs are merged.

For security reasons, configuration is only loaded from the repository's default branch,
changes made in pull requests from different branches or forks are ignored.

If you need more lower-level control over reading and merging configuration files,
you can `context.octokit.config.get(options)`, see https://github.com/probot/octokit-plugin-config.

@param fileName - Name of the YAML file in the `.github` directory
@param defaultConfig - An object of default config options
@param deepMergeOptions - Controls merging configs (from the [deepmerge](https://github.com/TehShrike/deepmerge) module)
@return Configuration object read from the file