allow symfony/filesystem 7

another composer.json / dependency change
thanks @peter17

3.0.1 (adds PHP 8.3)

• Improve github build coverage (add PHP 8.3 build step)
• Update psalm / fix niggles it moaned about
• Allow symfony/process 7.0 (thanks @peter17)

PHP 8.0 +

Bumps dependent libraries and the minimum PHP version increases to 8.0. Thanks to @wvdongen

Adds OS accuracy / script element support

• Refresh github action / psalm checks for PHP 7.2 <-> 8.0
• Add OS accuracy and script element support (See #2 ; thanks @wvdongen )
• Add support for Symfony Process 5 (See #1 ; thanks @wvdongen )