[5.5] Add support for unicode variable names (phpdotenv#546)

Co-authored-by: Thor Erik <[email protected]>

[4.3] Fix issue where line ending in `="` is incorrectly marked as a …

…multi-line start (phpdotenv#545)

Cleanup

Upgraded static analyzers

PHP 8.1 compatibility fixes

Update composer.json

Add support for BOM-signed env files (phpdotenv#501)

Update composer.json

Upgraded static analyzers

Fix for PHPUnit 8 compatibility