code: public void updateMemberRole(final String memberId, final ConversationMemberRole role, final AVIMConversationCallback callback) {
      AVIMConversationMemberInfo info = new AVIMConversationMemberInfo(this.conversationId, memberId, role);
      Map<String, Object> params = new HashMap<String, Object>();
      params.put(Conversation.PARAM_CONVERSATION_MEMBER_DETAILS, info.getUpdateAttrs());
      boolean ret = InternalConfiguration.getOperationTube().processMembers(this.client.getClientId(), this.conversationId,
              getType(), JSON.toJSONString(params), Conversation.AVIMOperation.CONVERSATION_PROMOTE_MEMBER, callback);
      if (!ret && null != callback) {
        callback.internalDone(new AVException(AVException.OPERATION_FORBIDDEN, "couldn't start service in background."));
      }
    }
docs: 更新成员的角色信息
  @param memberId  成员的 client id
  @param role      角色
  @param callback  结果回调函数