Fix deprecation warnings in commands

[jury89]

This PR a follow up of #105 and it's addressing the following deprecation warnings that I'm getting when using Symfony 6.1 and the latest version of the oauth2 server bundle.

2022-10-13T07:48:25+00:00 [info] User Deprecated: Since symfony/console 6.1: Relying on the static property "$defaultName" for setting a command name is deprecated. Add the "Symfony\Component\Console\Attribute\AsCommand" attribute to the "League\Bundle\OAuth2ServerBundle\Command\CreateClientCommand" class instead. 2022-10-13T07:48:25+00:00 [info] User Deprecated: Since symfony/console 6.1: Relying on the static property "$defaultName" for setting a command name is deprecated. Add the "Symfony\Component\Console\Attribute\AsCommand" attribute to the "League\Bundle\OAuth2ServerBundle\Command\UpdateClientCommand" class instead. 2022-10-13T07:48:25+00:00 [info] User Deprecated: Since symfony/console 6.1: Relying on the static property "$defaultName" for setting a command name is deprecated. Add the "Symfony\Component\Console\Attribute\AsCommand" attribute to the "League\Bundle\OAuth2ServerBundle\Command\DeleteClientCommand" class instead. 2022-10-13T07:48:25+00:00 [info] User Deprecated: Since symfony/console 6.1: Relying on the static property "$defaultName" for setting a command name is deprecated. Add the "Symfony\Component\Console\Attribute\AsCommand" attribute to the "League\Bundle\OAuth2ServerBundle\Command\ListClientsCommand" class instead. 2022-10-13T07:48:25+00:00 [info] User Deprecated: Since symfony/console 6.1: Relying on the static property "$defaultName" for setting a command name is deprecated. Add the "Symfony\Component\Console\Attribute\AsCommand" attribute to the "League\Bundle\OAuth2ServerBundle\Command\ClearExpiredTokensCommand" class instead. 

[chalasr]

Thank you @jury89.