配置sentinel基于nacos持久化时，有rule-type搞不清楚

    sentinel:
      transport:
        dashboard: 192.168.56.101:9015
        client-ip: 192.168.56.1
        port: 8719
      datasource:
        ds2:
          nacos:
            server-addr: 192.168.56.101:8848
            username: nacos
            password: nacos
            data-id: sentinelRule.json
            group-id: DEFAULT_GROUP
            data-type: json
            # 规则类型，取值见： com.alibaba.cloud.sentinel.datasource.RuleType 会对应到dashboard的栏目中去
            rule-type: flow

这个取值在com.alibaba.cloud.sentinel.datasource.RuleType

	/**
	 * flow.
	 */
	FLOW("flow", FlowRule.class),
	/**
	 * degrade.
	 */
	DEGRADE("degrade", DegradeRule.class),
	/**
	 * param flow.
	 */
	PARAM_FLOW("param-flow", ParamFlowRule.class),
	/**
	 * system.
	 */
	SYSTEM("system", SystemRule.class),
	/**
	 * authority.
	 */
	AUTHORITY("authority", AuthorityRule.class),

对应的其实时sentinel dashboard的栏目，就时这个作用