public static String buildInstanceParentPath(final String serviceName) {
        return String.join(SEPARATOR, ROOT_PATH, "instance", serviceName);
    }
Build instance parent path string.
build child path of "/shenyu/register/instance/serviceName

@param serviceName serviceName
@return the string
shenyu-registry/shenyu-registry-api/src/main/java/org/apache/shenyu/registry/api/path/InstancePathConstants.java