IntVal rule throws E_DEPRECATED warning in PHP 8.1

[fabacino]

Calling ctype_digit with something other than a string is deprecated in PHP 8.1

❯ vendor/bin/phpunit tests/unit/Rules/IntValTest.php                                                                                                                                      
PHPUnit 9.5.10 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.1.0
Configuration: /home/www/validation/phpunit.xml.dist

.............
Deprecated: ctype_digit(): Argument of type stdClass will be interpreted as string in the future in /home/www/validation/library/Rules/IntVal.php on line 39
.
Deprecated: ctype_digit(): Argument of type array will be interpreted as string in the future in /home/www/validation/library/Rules/IntVal.php on line 39
.
Deprecated: ctype_digit(): Argument of type null will be interpreted as string in the future in /home/www/validation/library/Rules/IntVal.php on line 39
...
Deprecated: ctype_digit(): Argument of type float will be interpreted as string in the future in /home/www/validation/library/Rules/IntVal.php on line 39
..
Deprecated: ctype_digit(): Argument of type bool will be interpreted as string in the future in /home/www/validation/library/Rules/IntVal.php on line 39
.
Deprecated: ctype_digit(): Argument of type bool will be interpreted as string in the future in /home/www/validation/library/Rules/IntVal.php on line 39
...
Deprecated: ctype_digit(): Argument of type float will be interpreted as string in the future in /home/www/validation/library/Rules/IntVal.php on line 39
.                                         25 / 25 (100%)

Time: 00:00.012, Memory: 6.00 MB

OK (25 tests, 25 assertions)

[alganet]

Nice! Let's fix it.

I'm approving the CI runs on #1374 and reviewing the change (I'm a little rusty, might take one or two days). Let me know if I can help you with anything else!

[nickl-]

Fixed #1374