Fix more PHP 8.4 deprecation errors

[MurzNN]

In the PR #301 some deprecation errors were fixed. I updated to the 10.12.0 release, but still having PHP deprecation issues:

Deprecated: {closure:Commercetools\Client\MiddlewareFactory::createRetryNAMiddleware():69}(): Implicitly marking parameter $response as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/web/vendor/commercetools/commercetools-sdk/lib/commercetools-base/src/Client/MiddlewareFactory.php on line 74

Deprecated: Commercetools\Api\Client\Resource\ResourceByProjectKey::__construct(): Implicitly marking parameter $client as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/web/vendor/commercetools/commercetools-sdk/lib/commercetools-api/src/Client/Resource/ResourceByProjectKey.php on line 24

There are more than 1000 places where we should fix this. But seems these files are auto-generated, so seems we need to fix this in the generator, and then - regenerate the files.

[jenschude]

This should be fixed with #322 now and with release 10.13.0

[stevekarsch]

It looks like the 10.13.0 release fixed a number of these issues but I'm still seeing:

PHP Deprecated: Commercetools\Client\ClientCredentials::__construct(): Implicitly marking parameter $scope as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/vendor/commercetools/commercetools-sdk/lib/commercetools-base/src/Client/ClientCredentials.php on line 41 PHP Deprecated: Commercetools\Client\CachedTokenProvider::__construct(): Implicitly marking parameter $cacheKey as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/vendor/commercetools/commercetools-sdk/lib/commercetools-base/src/Client/CachedTokenProvider.php on line 33

[jenschude]

As psalm wasn't reporting these deprecations i added now phpstan for finding the missing ones.

Released 10.13.1 which should now remove all of them