MySQL 8.0.19支持输入3次错误密码，锁定账户功能
例子：
>CREATE USER 'hechunyang'@'localhost' IDENTIFIED BY '123456' FAILED_LOGIN_ATTEMPTS 3 PASSWORD_LOCK_TIME 3;
FAILED_LOGIN_ATTEMPTS：代表尝试失败的次数
PASSWORD_LOCK_TIME：代表锁定的时间，单位天，这里为锁定3天。
如果设置UNBOUNDED，代表锁定永久，直到手工解锁。
故意输错3次以上密码，账户被锁定，如下所示：
# mysql -hlocalhost -uhechunyang -p123456789 -S /tmp/mysql_hcy.sock mysql: [Warning] Using a password on the command line interface can be insecure. ERROR 3955 (HY000): Access denied for user 'hechunyang'@'localhost'. Account is blocked for 3 day(s) (3 day(s) remaining) due to 3 consecutive failed logins.
手工解锁：
alter user hechunyang@'localhost' ACCOUNT UNLOCK;
