Support PHP 8.0 (Propaganistas#162)

Add getRawNumber() method

Laravel 8 (Propaganistas#154)

* Update composer.json

* Update tests.yml

* Update tests.yml

Drop support for Laravel 5.* (Propaganistas#144)

* Update composer.json

* Update tests.yml

Laravel 7 support (Propaganistas#136)

* Add L7 + PHP7.4

* Update composer.json

Remove ambiguous getCountries method

Support mixed case country fields (fixes Propaganistas#117)

Make PhoneNumber macroable

Resolve number types in Rule class (Propaganistas#112)

Ensure __toString() returns a string (fixes Propaganistas#105)