Description:
------------
When attempting to use password_hash with PASSWORD_ARGON2I as the algo, PHP throws 2 warnings.
1 - Undefined constant PASSWORD_ARGON2I
2 - password_hash() expects parameter 2 to be integer, string given.

Test script:
---------------
<?php
echo phpversion();
echo password_hash('password', PASSWORD_ARGON2I);

Expected result:
----------------
7.2.5
...some hash....

Actual result:
--------------
/usr/local/bin/php /-REDACTED-/test.php
7.2.5
Warning: Use of undefined constant PASSWORD_ARGON2I - assumed 'PASSWORD_ARGON2I' (this will throw an Error in a future version of PHP) in /-REDACTED-/test.php on line 3

PHP Warning:  Use of undefined constant PASSWORD_ARGON2I - assumed 'PASSWORD_ARGON2I' (this will throw an Error in a future version of PHP) in /-REDACTED-/test.php on line 3
Call Stack:
PHP Stack trace:
    0.0001     387040   1. {main}() /-REDACTED-/test.php:0
PHP   1. {main}() /-REDACTED-/test.php:0

PHP Warning:  password_hash() expects parameter 2 to be integer, string given in /-REDACTED-/test.php on line 3

PHP Stack trace:
Warning: password_hash() expects parameter 2 to be integer, string given in /-REDACTED-/test.php on line 3

PHP   1. {main}() /-REDACTED-/test.php:0
PHP   2. password_hash() /-REDACTED-/test.php:3
Call Stack:
    0.0001     387040   1. {main}() /-REDACTED-/test.php:0
    0.0001     387072   2. password_hash() /-REDACTED-/test.php:3


Process finished with exit code 0