added output to action execution

[Bullrich]

Added an output to the action.

It will return a stringified JSON of type:

type PullRequestReport = {
  /** List of files that were modified by the PR */
  files: string[];
  /** List of all the failed review requirements */
  reports: {
    /** The amount of missing reviews to fulfill the requirements */
    missingReviews: number;
    /** The users who would qualify to complete those reviews */
    missingUsers: string[];
    /** If applicable, the teams that should be requested to review */
    teamsToRequest?: string[];
    /** If applicable, the users that should be requested to review */
    usersToRequest?: string[];
  }[];
};

Resolves #17 and resolves #43

[mordamax]

👍