lib/plugins/aws/deployList/index.js/AwsDeployList/listDeployments
class AwsDeployList:  listDeployments() {
    const service = this.serverless.service.service;
    const stage = this.provider.getStage();

    return this.provider.request('S3',
      'listObjectsV2',
      {
        Bucket: this.bucketName,
        Prefix: `serverless/${service}/${stage}`,
      }
    )
    .then((response) => {
      const directoryRegex = new RegExp('(.+)-(.+-.+-.+)');
      const deployments = findAndGroupDeployments(response, service, stage);

      if (deployments.length === 0) {
        this.serverless.cli.log('Couldn\'t find any existing deployments.');
        this.serverless.cli.log('Please verify that stage and region are correct.');
        return BbPromise.resolve();
      }
      this.serverless.cli.log('Listing deployments:');
      deployments.forEach((deployment) => {
        this.serverless.cli.log('-------------');
        const match = deployment[0].directory.match(directoryRegex);
        this.serverless.cli.log(`Timestamp: ${match[1]}`);
        this.serverless.cli.log(`Datetime: ${match[2]}`);
        this.serverless.cli.log('Files:');
        deployment.forEach((entry) => {
          this.serverless.cli.log(`- ${entry.file}`);
        });
      });
      return BbPromise.resolve();
    });
  }