[Validator] Contraint Range Date

[timglabisch]

the Range Contraint supports Dates (as Strings), see https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Validator/Tests/Constraints/RangeValidatorTest.php#L339

this isn't mention in the documentation right now.
http://symfony.com/doc/current/reference/constraints/Range.html#min

[xabbuh]

@timglabisch Thank you for reporting it. Luckily, @webmozart already started to work on this in #4143.

[xabbuh]

This isn't limited to the Range constraint, but also affects the comparison constraints like EqualTo, GreatherThan, and so on.