Add capability required by new image

roles/matrix-coturn/templates/systemd/matrix-coturn.service.j2

@@ -17,6 +17,7 @@ ExecStart={{ matrix_host_command_docker }} run --rm --name matrix-coturn \
 			--log-driver=none \
 			--user={{ matrix_user_uid }}:{{ matrix_user_gid }} \
 			--cap-drop=ALL \
+			--cap-add=NET_BIND_SERVICE \
 			--entrypoint=turnserver \
 			--read-only \
 			--tmpfs=/var/tmp:rw,noexec,nosuid,size=100m \