Added support of mask on the table level

[PovilasKorop]

Without this change, the documentation example works incorrectly: dumps the DB but doesn't use the correct mask character.

return [
    'default' => DumpSchema::define()
        ->table('users', function ($table) {
            $table->mask('password', '-');
        })
];

[mpociot]

thank you, Povilas. Took me some time, sorry :D

[PovilasKorop]

@mpociot no worries, you made it in February, just different year :)