code: function validGh (opts) {
    if (!opts.ghrelease) {
      return Promise.resolve(true)
    }
  
    if (!opts.ghtoken) {
      return Promise.reject(new Error('Missing GitHub access token. ' +
                                      'Have you set `AEGIR_GHTOKEN`?'))
    }
    return Promise.resolve()
  }
docs: Check if there are valid GitHub credentials for publishing this module