Upgrade guide

1. Make sure rector is installed:
   • composer require rector/rector --dev
   • Run vendor/bin/rector if you don't have a rector.php config file
2. Add the necessary rector sets in your rector.php config file:

return RectorConfig::configure()
    // …
    ->withSets([
        TempestSetList::TEMPEST_20,
    ]);

3. Run vendor/bin/rector