Add two and remove one Google Group

Author: dhruvkb

content/community/community-team/engagement-channels/contents.lr

@@ -77,18 +77,25 @@ We also have a few mailing lists where we communicate announcements and the
 like. Join us on our [Google Group mailing lists](/community/#mailing-lists) if
 you are, or want to be, a part of the community.
 
-### Community Team group
+### Developer group
 
-This group is for all CC tech staff and everyone on the Community Team.
+This group is for all developers who are associated or related to the 
+open-source community around our projects.
 
-**Address:** community-team@creativecommons.org
+**Address:** cc-developers@creativecommons.org
 
-### Community Team: Core group
+### Usability Announcements group
 
-This group is for Community Team members who have the role of Community
-Maintainers or that of Project Collaborators and higher.
+This group is for all people participating in our Usability testing sessions.
+Announcements of upcoming tests are made in this group.
 
-**Address:** community-team-core@creativecommons.org
+**Address:** usability-announce@creativecommons.org
+
+### Community Team group
+
+This group is for all CC tech staff and everyone on the Community Team.
+
+**Address:** community-team@creativecommons.org
 
 ## GitHub