Current implementation does not work with GitHub teams. It only includes GitHub organizations as Jenkins groups.
Worse, giving access to "Owners", "Developers", "Administrators" and so on actually gives access to GitHub organizations named "Owners"...!

Suggestion:

• keep GitHub organization to Jenkins group mapping
• add GitHub teams mapping to Jenkins group with the following form: "organization*team" using an asterisk as separator (any separator not allowed by GitHub in team names could be used, but the slash generates browsing errors in Jenkins).