Add privacy attribute to Team objects

Closes #430

src/github3/orgs.py

@@ -27,6 +27,9 @@ def _update_attributes(self, team):
         self.members_urlt = URITemplate(team["members_url"])
         self.name = team["name"]
         self.permission = team["permission"]
+        self.privacy = team.get(
+            "privacy"
+        )  # TODO: Re-record cassettes to ensure this exists
         self.repositories_url = team["repositories_url"]
         self.slug = team["slug"]
 
@@ -302,6 +305,10 @@ class ShortTeam(_Team):
         The level of permissions this team has, e.g., ``push``, ``pull``,
         or ``admin``.
 
+    .. attribute:: privacy
+
+        The privacy level of this team inside the organization.
+
     .. attribute:: repos_count
 
         The number of repositories this team can access.