FilterVar casting result to bool

[tlangens]

PHP's filter_var returns filtered data or false if the filter fails. Respect\Validation's FilterVar uses Callback to call filter_var, which in turn casts the result to bool. The result of this is that if valid data from filter_var casts to false, the validator rejects the input even though it passed validation by filter_var.
For example:

filter_var('0', FILTER_VALIDATE_INT); // Valid input, returns 0, a valid integer.
(new FilterVar(FILTER_VALIDATE_INT))->validate('0'); // Valid input, returns false.

[alganet]

Duplicated here: #1387

A fix for it is already in place and targeted for the next release 🐼 I'll close this when it is on packagist.

[henriquemoody]

Version 2.3 was released about a week ago.

I'm closing this now 🐼