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

@param registerServiceName registerServiceName
@return the string
shenyu-register-center/shenyu-register-common/src/main/java/org/apache/shenyu/register/common/path/RegisterPathConstants.java