why not support IPV6

[cupidove]

shardingsphere-elasticjob/elasticjob-infra/elasticjob-infra-common/src/main/java/org/apache/shardingsphere/elasticjob/infra/env/IpUtils.java

Line 147 in 32202a2

&& !isIp6Address(inetAddress) && inetAddress.isReachable(100);

[TeslaCN]

We don't know whether ElasticJob works well under IPv6 Environments. You may try removing the limitation if you are interested in this.