happa release v1.39.1

Changes

• Set cluster labels via the Management API: use kubectl label command instead of kubectl patch by @marians in https://github.com/giantswarm/happa/pull/3314
• Create a client certificate via the Management API: improve groups placeholder and explanations by @marians in https://github.com/giantswarm/happa/pull/3313
• Upgrade Cluster API resources used to version v1beta1 by @kuosandys in https://github.com/giantswarm/happa/pull/3308
• Handle the rare case where a request for Release resources returns no items key in the response by @gusevda in https://github.com/giantswarm/happa/pull/3312

Full Changelog: https://github.com/giantswarm/happa/compare/v1.39.0...v1.39.1