Remove "sokil/php-isocodes" as a dependency

Fix list of top-level domains

Remove the unnecessary use of mb_detect_encoding()

First release of 2.2 series

First release of 2.1 series

New rules
---------

- Decimal

New features
------------

- Make "HexRgbColor" rule case-insensitive
- Allow file-related rules to validate PSR-7 interfaces
- Auto-resolve exception namespaces

Improvements
------------

- Allow optional space for greek postal codes
- Remove "Key" prefix from KeyException message
- Update list of top-level domains

PHP support
-----------

Drop support for PHP 7.2.

Fix list of top-level domains

Fix overwritten rule names on "AbstractRelated"

Fix missing domain validation in "FilterVar" rule

Fix unexpected behavior on "IntVal" rule

Fix list of top-level domains