Update MSC1929 integration

roles/custom/matrix-base/templates/static-files/well-known/matrix-support.j2

@@ -1,6 +1,6 @@
 #jinja2: lstrip_blocks: "True"
 {
-    "admins": {{ matrix_homeserver_admin_contacts|to_json }}
+    "contacts": {{ matrix_homeserver_admin_contacts|to_json }}
     {% if matrix_homeserver_support_url %},
         "support_page": {{ matrix_homeserver_support_url|to_json }}
     {% endif %}