Bump PHP requirement to 8.1 (#34)

Fix case where scanned class name is NULL (#31)

* Fix bug related to #920

* Update phpstan

Allow newer version of symfony filesystem (#30)

Refs #28

Replace webmozart/path-util with symfony/filesystem (#28)

Co-authored-by: dantleech <[email protected]>

Fix 8.0 deps

Update test

Use composer install to dump autoload, as by default composer 2 is not
generating the dev autoload rules

Update deps

Use Path::isAbsolute to check absolute path

Ensure class names are unqiue

Performance: Move existing path filter until after we know it's a valid

...prefix. This caused severe performance issues in long running processes.