Regarding
https://getcomposer.org/doc/articles/scripts.md
The sample contains
"post-package-install": [
"MyVendor\MyClass::postPackageInstall"
],
public static function postPackageInstall(PackageEvent $event)
Observation
composer run-script post-package-install
Argument #1 ($event) must be of type Composer\Installer\PackageEvent, Composer\Script\Event given,
Composer version: 2.5.5
Windows 10
Is the sample working for you?