How to manage collaborator rights in Github?

Sorry, this functionality is not provided by Github. Collaborators on a Github repository have complete control over the issues tracking system for a repository. Specifying whether a collaborator can manage labels or not is not a feature provided by Github

You can add them as collaborators. From the setting page of your repository.

UPDATE: But for user accounts collaborators have the same rigths, you can not give different permissions unless you have an organization account.

Since May 23rd 2019 (6 years later), check out the Triage and maintain roles (beta) (if your repository is part of an organization)

Administrators of organization-owned repositories can now assign “triage” and “maintain” roles to collaborators and teams as part of a public beta preview.

If a contributor proves their ability to drive technical discussions or lead development of your project, you can empower them to take on additional issue or repository management responsibilities without needing to also grant the ability to modify your project’s source code or change potentially destructive repository settings.

The new roles are immediately available to some organizations today and will be available to all organizations on the Free, Team, and Enterprise Cloud plans in the coming weeks.

See the updated "Repository permission levels for an organization".