function linkedInClient() {
  // LinkedIn OAuth 2 setup
  // TODO: Configure the `linkedin.client_id` and `linkedin.client_secret` Google Cloud environment variables.
  return require('node-linkedin')(
      functions.config().linkedin.client_id,
      functions.config().linkedin.client_secret,
      `https://${process.env.GCLOUD_PROJECT}.firebaseapp.com/popup.html`);
}
Creates a configured LinkedIn API Client instance.