Wrong values of constants in SearchFilters

[padhie]

The constants of the file xivapi-php/src/XIVAPI/Api/SearchFilters.php seem to be wrong.
It is actually about the constants LESS_THAN and LESS_THAN_OR_EQUAL_TO.

    const EQUAL_TO                  = '=';
    const GREATER_THAN              = '>';
    const GREATER_THAN_OR_EQUAL_TO  = '>=';
    const LESS_THAN                 = '>';
    const LESS_THAN_OR_EQUAL_TO     = '>=';

[vekien]

Fixed ty!